I think there are two ways of reading the claim that a traumatized person can't be responsible for other peoples' comfort. The first is reasonable: nobody is really responsible for anyone else's comfort. We have to take care of ourselves at the end of the day, so mentally healthy people especially shouldn't rely on traumatized people to make them comfortable.
The second is unreasonable: traumatized people, more than anyone, have no obligation to do the basic things that make other people comfortable, in virtue of their trauma.
I think the post just makes it sound a little too much like the second interpretation, because otherwise why focus on traumatized people in the first place? I think that's what's getting under most peoples' skin.
The part that's bothering people is the "traumatized people can't be responsible for other people's comfort." It sounds too much like "I'm sorry if my reaction made you uncomfortable, but I have trauma and so I'm not responsible."