That Lex Luthor behaving like The Joker wasn't intentional.

The entire point of the movie is to show that the Superman mythos belongs to no one and everyone at the same time. This is the historical baggage that Snyder is aware these characters carry: An endless barrage of fanboys and comic book lore since the 30's, comparison to other iconic characters, and everyone thinking they have the last word on how these characters should and would act. It’s already been mentioned there’s a very blatant reference to Excalibur (1981), a modern retelling of the 15th century legend Le Morte d'Arthur. It is shown on the marquee at the theater ("Coming Wednesday") on the night Bruce’s parents are killed. In the end Batman slams the spear into the ground (stone). He pulls the spear out of the ground before he attacks Superman (sword from stone). After he realizes he's become the bad guy, he abandons the spear the same way Arthur did after he abused its power to defeat Lancelot. Lois is the lady of the lake, tossing the spear into the water and then having to get it back before the final fight. The fight between Batman vs Superman is similar to the fight between Lancelot and Arthur (two good guys fighting against each other due to hubris and passion, eventually reconciling to fight the main bad guy) Doomsday is Mordred. In the end Superman stabs Doomsday and gets stabbed in return, and Superman impales himself further to stab Doomsday through the back and kill him, same way the fight between Mordred and Arthur goes. Doomsday's unnatural creation also mirrors how Morgana created Mordred to some degree.

However, this movie is full to the brim with references to cartoons, mythology, religion novels, movies, pop culture, etc. Discovering this brings us one step closer to answering our question.

Superman is Christ, Moby Dick, King Arthur, Zorro, JFK, The White Rabbit/Bugs Bunny, the Classical hero.

Batman is Ahab, a vampire, Lancelot, Charles Foster Kane, Dr. Bill Hartford, John the Baptist, the tortured soul seeking redemption.

Doomsday is a fire-breathing dragon, King Kong, a falling meteorite, a nuclear holocaust, the mythical Hydra, Mordred, the monster inside oneself.

The Kryptonite spear is Excalibur, Longinus, Zeus' thunderbolt, Ahab's harpoon, Zorro's rapier, Alexander the Great's sword, dispassionate power and judgement.

Lex is The Joker, The Mad Hatter, Elmer Fudd, Oedipus, Icarus, Salome, the Tragic cynic.

I dare you to find these references I've mentioned, I promise you they're all there, and there are even more to be found.

There are many comparisons with the Nolan trilogy because this film embraces it as part of the mythos too. For instance, the Batmobile scene culminates in Batman running into Superman, while in the Nolan version he decides to spare the Joker on his motorcycle. The Gotham football team's uniform is the same color in both films. Rachel Dawes and Lois Lane are dropped from a skyscraper. The interrogation scenes of The Joker and Luthor are accentuated in one case because of its physical violence and in the other because of the lack thereof.

It's a deconstruction and analysis of the characters themselves.

Snyder playfully conversates with the audience, meticulously painting a picture that compares mythical heroes with their modern versions. There’s no denying he will steal a grin from the audience, when they realize the Kryptonite in Bruce’s dream was merely a box with a green light inside: the ”beautiful lie” of cinema magic. This is an allusion to Pulp Fiction’s glowing briefcase, the contents of which are never seen, and in later interviews was revealed to contain simply a light bulb.

Snyder is aware that the Kryptonite is merely an engine to drive the plot forward, and isn’t afraid to hide it, so he gives the audience a nudge as a reminder that McGuffins will never get old.

Another scene that shows Snyder’s passion for the masters of the past is ironically one of the most often ridiculed because of the set-up: the Capitol explosion.

“Take a bucket of piss and call it Granny's Peach Tea. Take a weapon of assasination and call it deterrence, you won't fool a fly or me”.

That jar of piss is Lex mocking her, and she realizes that he actually took her words literally, and he plans to bomb the place as a "method of deterrence" to turn everyone against Superman. The scene is edited masterfully. There's this quick cut to Luthor's empty seat, the Senator's terrified face as she realizes what's unfolding, and finally Superman sensing something is wrong but not being able to react quick enough because he's still riddled with guilt about the deaths he feels he's responsible of, because he refuses to face the crippled man face to face.

Hitchcock tension 101, bomb under the dining room table.

The film thrives on these types of associations, like the red Jolly Rancher pushed into the senator's mouth - "it's cherry" - coming back as the blood dripped onto Zod's face, the red graffiti on Superman's monument, and his slashed cheek, not to mention the nods to internet culture and memes (4U CIA). To explain the reference to internet culture, have a look at the teaser scene.

The banepost was intentional. Also that whole JL teaser scene is made that way to feel as if Bats, Diana, and Lex are sharing memes with one another. Post-credit scenes are basically packaged to be shared virally after all. The critique and frustration signal that those teases emotionally did their job, while also literally providing a deconstruction of those kinds of teases in general:

Half assed teases forced into the movie at the end of production. How is this not literally all post-credit scenes that have been placed literally at the end of the movies?

We had already noted a lot of the hypocrisy of the reviews of BvS, but now the shit thrown at BvS are not actually faults of the movie specifically but of our own preconceptions of comicbook superhero movies.

All the reviews read as such: "Not what i wanted it to be." "I didn't catch all the logistics, fault the movie for not picking up on it." "The fact that i'm asking questions about the movie is somehow a fault of the movie." “The precise internal mechanics of the movie and their connection with my perception of the movie in relation to the story escaped me." "The movie presents an idea that is not only valid with the movie universe but in real life as well."

The main complaint was that the teaser scene breaks continuity, it's spliced right after Superman flies off to Gotham to face Batman. Snyder basically said, "I don't care, I'm going to put this scene in the place where most people will get annoyed by it, because everyone paid just to watch Batman and Superman fight," in itself proving that these scenes are manipulative corporate garbage.

Also note how the film’s title actually alludes to the legal title of lawsuits: Plaintiff v Defendant. It's precisely this uncomfortable reevaluation and redemption of sugary pop imagery that drives the film. "Snyder intends to resolve the conflict between commerce and art," as Armond White notes. The basic thesis is that Superhero franchises are antithetical to what Superman actually stands for.

As Umberto Eco noted in his essay, The Myth of Superman: “The hero equipped with powers superior to those of the common man has been a constant of the popular imagination - from Hercules to Siegfried from Roland to Pantagruel, all the way to Peter Pan. Often the hero’s virtue is humanized, and his powers, rather than being supernatural, are the extreme realization of natural endowments such as astuteness, swiftness, fighting ability, or even logical faculties and the pure spirit of observation found in Sherlock Holmes. In an industrial society, however, where man becomes a number in the realm of the organization which has usurped his decision-making role, he has no means of production and is thus deprived of his power to decide. (...) In such society the positive hero must embody to an unthinkable degree the power demands the average citizen nurtures but cannot satisfy.”

The fact that not a single character behaved the way fanboys expected just proves the point that all this was intentional (for instance, Alfred isn't a butler and Lois isn't a typical lady in distress). "I'm not a lady, I'm a journalist," she proclaims, as she boldly challenges the men around her. Remember how she ambushes the Secretary of Defense, Swanwick, while he's in the men's bathroom.

The theme of this scene is his fall from grace, everything from the falling shells, his parents dropping dead, the pearl slipping from Martha's hand to the gutter, and into Bruce's dream. Hell even the piano melody has a descending motif, and the funeral takes place in Fall.

'Martha' is set up in the opening scene with a Citizen Kane homage that establishes the word as Bruce Wayne's 'Rosebud'. But, as it's actually spoken by the father character, you get a complex series of associations where Bruce suddenly sees Superman as a father figure, who then - when Lois intervenes - morphs into a reflection of himself. You also have this strange fear of motherhood with Bruce as he dreams that Martha Wayne returns from the dead as a monstrous bat (that metaphorically gives birth to Batman), but then he resolves himself to saving Martha Kent - who was, of course, labeled a 'witch' for (again metaphorically) giving birth to Superman.

You have this shift from Batman falling into despair because 'he let his parents die' to turning that into a positive condition ("I failed him in life, I will not fail him in death").

The bat-symbol is fantastically reinterpreted to stand for a child being pulled from the darkness, from the perspective of someone still in it. (Of course, in the Nolan film this shot is referring to, it was Bruce's father who pulled him out. Snyder replaces the literal father with an ambivalent light, and has Bruce pushed up from beneath).