I get worried about throwing derogatory labels on anybody we think fits a certain 'group.'
The thing is, there is a difference between 'sexist rager who just wants to put the dominant sex down' and rational person who see's something wrong in an argument and calls another out out for some sort of abuse.
For example, if I say something like "kys" to another person, you could say, "hey don't do that" or, "that wasn't okay dude," and if I don't want to deal with that I can just brand you an SJW and ignore you.
This is because we have come to use the term derogatorily to refer to anyone who speaks out against us from the stance that what we say is sexist or not 'PC.' Rather than face the possibility that I may have just hurt somebody, I can ignore you and continue to feel like I've done nothing wrong.
That's not how arguing works; it's avoiding the issue. And it results in me being able to go about my life, maybe hurting people, maybe not. But I'll never know, and never change, because I refuse to learn how to treat others properly.