Why do people often complain about fictional characters? They say they're whiny or complain too much or don't handle things well. Bella from Twilight and Kylo Ren from Star Wars come to mind as two big such characters. But when people complain about characters' reactions, do they think about how they themselves would react to the same circumstances that these fictional character go through?
Take Kylo. He didn't find out until he was in his twenties that Darth Vader was his grandfather--and he didn't even find out because his family told him. He found out because the secret went public. So he found that out and he was having some struggles with staying on the right path and then he had that encounter with Luke---so of course all that would mess someone up. Does that mean he isn't responsible for his actions? No, of course not. I'm just saying that the right choice isn't always easy or even clear when you're in the middle of it all. It's easy to blame fictional characters for things that we might fail at ourselves.
I've talked at some point about how The Silver Chair is one of the least favorite books out of The Chronicles of Narnia. And it also happens to be the book in which all of the characters keep failing. They have clear tasks and yet they just keep botching it all up (though Aslan is there to help them through it all, anyway, and they do succeed in the end). So it's hard to dwell in that story because it reminds us of our own shortcomings.
That's why we often prefer our fictional characters to act in superhuman ways: we want to believe that we can, too. Sure, characters that are relatable are great, but we'd rather relate to their positive traits or even simply their struggles than their failures. We want to believe that we're tempted to be bystanders like Han Solo but we come through in the end, or that we're shaken by some sort of awful realization like Luke was but that we use that knowledge for good. But we don't want to know that we're falling apart like Kylo. We don't want to know that we're botching everything up like Jill and Eustace and Puddleglum did in The Silver Chair.
That's why we criticize fictional characters. Failure hurts but victory gives us hope. We can learn from the failure, but sometimes we just like fiction to feel good.