Sure, and I wouldn't be bringing up the same subject when consoling a friend who was just treated this way by their partner, or talking to a friend who just treated their partner this way. But the context here is the discussion section of a post of a screenshot of a post of a stranger recounting their experience. I'm not trying to help Silverwing Secundus; they're not here in this thread. There's a lot of discussion in this comment section about common experiences and gender relations. So it seems perfectly natural to bring up one of the most significant influences on the way people of opposite genders interact in our society.
That's not what that word means. “patriarchs” aren't men in general, that's why it's possible (and in fast true) that the patriarchy harms people of all genders.
As this post demonstrate, men don't benefit from it, e.g. it makes us live shorter, it encourages suppressing our emotion, it encourages our aggression. Because some (mostly) men in power benefit if we don't unionize, let ourselves be pressed into shit jobs or the military, and so on.
Read the other messages here and you might understand.