Anger is a healthy and normal human emotion. It’s okay to be angry. Just because someone gets angry doesn’t mean their point less valid.
Discrediting an argument because of judgement you made on the person having it us a famous fallacy called an

Ad hominem

https://en.m.wikipedia.org/wiki/Ad_hominem

If you disagree with my thoughts, that’s fine. Saying I’m wrong because I have normal human emotions such as anger, is not really arguing a valid point or providing any logic on why I’m wrong.
Trying to discredit me for having normal, human emotions isn’t really very logical, it’s a fallacy.
You might enjoy studying the field of logic. It’s a very interesting field!

To be fair, I’m indeed talking about JKR by going after who she is. But I’m not saying that she is wrong because of who she is, I’m saying she’s not an expert on gender, and thus there is no need to listen to her anymore than I would listen to say my grandma. I can’t figure out why we obsess about what she says when she’s not an authority on gender.