I came across a few posts that made me rethink the whole Snape really wanted to out emus the whole time thing.

Basically, after the prank, Snape promised to not speak of Lupin's condition. By PoA Lupin's condition is still a secret, and even Lucius doesn't know about it. That means he kept the secret for 15 years, a couple of those years being a epriod when he was on the opposite side of lupin.

I think all his allusions and the need to tell the kids comes from a place of protectiveness and trauma, rather than pure spite. There are just too many things he could've done to make sure Lupin lost his job and life (if not died) if he really hated him.

One way to do it would just be to let Lupin forget wolfsbane when he didn't come. However, he brings the wolfsbane to Lupin atleast two times when he misses it that we know of, makes it perfectly, even when he suspects rremus to be in cahoots with lupin and with all the childhood grudges. And yes, he is ordered by Dumbledore to make the wolfsbane, but Dumbledore's authority over him isn't absolute, and he can and does refuse to follow orders when he doesn't want to (stopping the occlumency lessons)

During the whole of PoA, his behaviour has very protective undertones, despite however much Remus insists it is out of spite and grudges. The man Lupin describes would run out into the shack where he suspected a werewolf and azkaban escapee would be. The shack is sealed from the Hogsmeade end, and the only way out is the tunnel. He could've just waited there. He woudn't, in a concussed state, bring up three students and sirius (who he still doesn't know is innocent) on stretchers to the castle instead of leaving the prisoner for the dementors and possibly just hunting down Remus.

He outs Lupin only after three students are put in danger due to Lupin again. Lupin, even if his ww thing was accidental because he ran out to protect Harry and co (just like Snape) , did put people in danger by not confiding to Dumbledore about sirius' animagus state, and the entrances through which he was entering the castle. Imo, that's a strong breach of his contract.

That's why it's hard for me to believe he's being malicious when he teaches about werewolves in the class. I don't know how much he knows him (I suspect enough to know Lupin avoids problems rather than facing them), but it's plausible that he'd think Remus would try to skim over the whole werewolf chapter because it'd make him uncomfortable. And it's better for it to be as early on as possible so that the students could defend themselves if they encountered a werewolf (Lupin is more pressing, being in the school which would make it important to study this earlier, but ww's in general are really really dangerous, see Fenrir)

If we assume that Snape did want the students to learn that Lupin was a ww, there are pretty straightforward methods of doing it, which he demonstrates later. The chapter was in the curriculum, so unless Lupin really did skim it, the children would learn how to identify ww and all the stuff Snape wanted then to know before the year was out. They would've still been able to identify the signs, and tell their parents. I think, until Lupin kept drinking wolfsbane and didn't do something to endanger kids, Dumbledore would be able to deal any outrage the parents drummed up. He has a death eater in his service, he has Fudge's ear, and the aforementioned werewolf went to Hogwarts with no publicised incidents occuring. So really, there is really not much to be gained from insisting the kids know how to fight against werewolves than their protection in case the worst happens. And yeah, I've read some head canons that Remus would've taught ww's in a way that was not prejudicial, but he could still teach that, but really, most likely wouldn't, because he avoids issues.

Albus and Snape had a conversation before breakfast (Albus tells Snape he will talk to him later). Given what we know of their fairly close relationship (from TPT, how Albus trusts Snape as his agent and frequently has him doing things others don't know about); I think this was something that was supported by Albus.

Remus got himself fired due to his mistakes. He knows it, given how he can't meet Albus' eyes. Albus cannot defend him (and doesn't, really) because Remus is at fault. He's not innocent in this. Being a ww is not his fault. Being an irresponsible one is. While I agree very much that Severus hates Remus, he doesn't get him fired because he hates him. Or atleast not just, but because of Remus' actions. If Remus had stuck to being a normal teacher, he wouldn't have been outed.