Thank you for making a meme of your own. But in all sincerity, I think almost everybody in Springfield hates Bart for all the terrible, rotten, indefensible things he's done over the years.
There was one episode in which Homer strangled Bart on live TV, and no one in Springfield complained.
There was an episode called "Love Is A Many-Strangled Thing", in which a psychologist named Dr. Zander denounced Homer for strangling Bart, but when Dr. Zander saw firsthand how horrible Bart was, Dr. Zander started strangling Bart himself.
There was an episode called "Boys of Bummer" in which everybody turned against Bart and drove him to attempt suicide because he lost a baseball game. I think a lot of people who hated that episode had only seen that specific episode and were thinking "How could they all be so mean to him for losing a baseball game?" The way I see it, they were mad at him not simply and solely for losing a baseball game, but for all the terrible, rotten, indefensibly horrible things he did in addition to losing a baseball game. Here's a link telling more about how horrible Bart is:
https://screenrant.com/worst-things-bart-simpson-done-ranked/
To me, Bart Simpson is the ten-year-old equivalent of Heath Ledger's Joker from The Dark Knight because he causes trouble just for the sake of causing trouble.