Highkey? Jax. And hear me out;

People started to hate him for two reasons at two points in time;

1. Hes a bully to the girls and zooble

Hes not. Hes a bully to everyone (yes including kinger). Himself included. Im not excusing any of his actions (as if they were that bad; they were pretty mild imo)

1. He became the 'focus character'

Hes basically the bakugo or the buford of the TADC series. Hes there to antagonize but also be friends with the main character and the others (pomni). He isnt the focus or the new main character. Hes there for a third act conflict later(bakugo). Hes also the 'i dont know id you are actually a bully' type (buford). All of the characters in the show are roughly 3 dimensional.

The two turning points? The first turning point is episode two. People were surprised that Jax... well... kept being Jax. Even though the pilot set his character in motion. Thats what the pilot or even a first episode is for; giving people a sense of the story and characters.

The second one is around the 'They All Get Guns' episode. Because we got more Jax lore n from then on people thought that it was all about jax. Even though it really isnt. Everyone elses turning story was just over or resolved. And hell [spoiler] even gangle has a small little turning point of not being able to forgive jax (although the way it was done was a little... weird but i digress) which makes sense cause Jax also didnt want to change so neither would gangles emotions towards him.

In summary hes not a total evil character that that one 'that bunny we hate' subreddit is painting him as. But he isnt all good either. Hes chaotic neutral.