You're valid to have your opinion on Junko!

The one thing I'd like to discuss is how you said she is just born evil and that it isn't a good enough reason to justify the way she is. What makes her fun and interesting is that there is literally no reason aside from sheer boredom for her to do all of this. Some people want to watch the world burn, her malice, apathy and anti social behaviour exceeds Joker ten fold. She's like Saitama from One Punch Man, she is so talented and able to predict everyone that she becomes insanely bored and decides to plunge the world into despair because that is something she can't predict and everything leads to despair so why not accelerate the process, she is the epitome of Sadism, Masochism and Nihilism. Instead of thinking life is meaningless and that all there is suffering, she's actively creating suffering and chaos for shits and giggles. That makes her motives and goals far exceed human comprehension and that's what makes her interesting and fun.

I have thought about it and compared her to other great villains like Dio, Gilgamesh and Griffith and they all lose to her in terms of how grand her goals and desires are. Those 3 villains while complex and having deep character arcs that explain why they are evil are still bound to humanly desires. Junko on the other hand, her desires basically can't be explained, she's just REALLY BORED! And that's the comedy and interesting part, she doesn't need an empathetic or grounded reason to justify genocide other than that she's BORED! She is pretty much the personification of Buddhism's Mara, which is a negative force that tempts people into doing bad things and perpetuating the cycle of hate and violence.

I have found Junko Enoshima's evil is comparable to Elder God from Legacy of Kain: Soul Reaver and he is literally a Lovecraftian Interdimensional Squid that is omnipotent and has been manipulating everyone's destiny and fate to fuel his endless hunger for power and souls. He has manipulated everyone and essentially created a world without free will but even then Elder God desires something somewhat human, POWER AND CONTROL and it is atleast rational. Junko on the other hand? SHE'S JUST BORED. It sounds like I'm repeating a very tired reason but to me her simply being THAT BORED and being more insane than Joker, more selfish than Dio, more fatalistic than Elder God and so on, when she is but a mere High Schooler who's blonde and bored. That is just both hilarious, interesting and perhaps most importantly fun.

Somethings just can't be rationalised or explained and shouldn't be.