[image description: a reddit comment by user evergreengoth. quote below]
People who have been hurt by cis men are sometimes angry. They want a target. They want to hurt the men who hurt them.
But they can't. Cis men are protected by privilege and systemic power that makes it so that woman, sometimes especially trans women, really don't have a lot of recourse.
It also feels good, if you're the right type of person and you hate yourself a little, to have someone below you that you can hurt so you can reassure yourself that at least someone else is lower than you. This is especially true if you're insecure in your own identity. It's why poor white people eat up racist ideologies; it feels good to punch down at someone when you yourself are feeling both inadequate and powerless. Anyone, including trans men who are insecure in their position, is vulnerable to giving into the temptation to pick a vulnerable target to go for. It's a way to feel big and build yourself up and when you're marginalized or hurting, that kind of thing becomes appealing, whether you realize it or not. Not everyone has this impulse, but enough do that it's a problem.
You can't hurt a cis man as easily because of all the privilege. They're just not very vulnerable.
But a trans man? A trans man is a man without any of that protection.
A trans man is a man you can *hurt.*
If that trans man gets to talk, though, and if he starts pointing out that he's as oppressed as you are, if he demonstrates that he's vulnerable and, in fact, a victim, just like you, then you don't get to feel good about it, especially if you've framed the justification for hurting him as though you're a victim who is punching up and entitled to act on your righteous anger. Men, whether directly or in more abstract ways through the pressures of patriarchy, have hurt you, and you're allowed to be angry and fight back. He's a man, so he's automatically an acceptable stand-in for who or what it is that you're angry at and want to hurt.
If he has a voice, it means you're punching laterally or punching down and you're as evil as the men who hurt you. You want to keep feeling big. You want to keep feeling like the harm you're doing is righteous justice. You want to feel like you're punching up. You don't want to be the bad guy. You just want a guilt-free outlet for the pain you're in.
If the fact that he's also a victim and more than innocent, and has had nothing to do with causing your pain, you don't get that guilt-free outlet because then you're as bad as whoever hurt you. You want to be the underdog hero, not the villain.
So you'd better get him to shut the fuck up, and if doing so allows you to hurt him more, so much the better because hurting him feels good.