I think this fandom’s biggest problem is that it always sees things in black and white.
I’m going to be a pain but:
Criticism isn’t hate and hate isn’t criticism.
You can like characters while being critical of them or their actions.
Even “good” characters have flaws and acknowledging that means you see them for the interesting and complex character that they are.
Character development means a character will change and learn from what happens to them. During that time, they will do good or bad things. It happens in almost all stories.
Characters who are “good” can do “bad” things and that doesn’t mean you have to dislike them or think one bad action means they’re bad forever. It’s always a lot more complicated than that.
Character who are “bad” can still be interesting and fascinating characters.
You don’t have to justify liking a character who do “bad” things. You only have to recognize and acknowledge they do bad things.
Just because a lot of people think something is true doesn’t mean it is.
There is always a context that explains how and why we perceive fictional characters. Our values are always influenced by the society we live in (with its prejudices and stereotypes).
What happens in the story is one thing. What happens in fandom is another. If your favorite character hates another character, you don’t have to automatically do the same. If the story makes two characters fight each other, you don’t have to recreate that fight in fandom.