Yeah, I’ve seen it said that sibling is like a built-in best friend. And the very best friends will curse you to the depths of hell with a straight face and hear you do the same, and still remain your best friend
That’s the whole reason trans rights, women rights and so on are talked about. Some people need a constant reminder that trans people are human, women are human and all the other minority groups are human as well. Because somehow that’s not obvious to them.