Why do we support Katniss but not Baltimore protestors?

You’ve managed to miss the point again.

Yeah, some people think those things, and some people don’t, and some think both are true, and some think neither. Complex situations yield a range of opinions.

When it comes to fiction — I mean, is there anyone who doesn’t support Katniss? She was explicitly created to be the hero in her story; you don’t really have any choice but to support her.