They absolutely do. They are by no means the majority, but extremes exist in any movement. There are “feminists” who think it’s all about sticking it to the man (literally) or proving feminine superiority. It’s like Christians who don’t read the Bible and think it’s all about damning the gross icky people to hell. That doesn’t mean they’re common (they aren’t), but I’ve seen a few crazies on Tumblr and Twitter.