What makes it possible?

When I was a little kid and I told my parents I was transgender, they started waking me up in the middle of the night to clip clothespins to the tips of my fingers. My mom started bringing cute little animals home, and one time I remember her wringing the neck of a tabbi striped kitten and forcing it's corpse inside my vagina, which she made me push out as if I were giving birth. I developed dissociative blackouts as a child because I didn't want to experience her torturing me.

I can't speak for every trans person, but many trans people have experienced very intense levels of hate from cis people, not excluding members of their own family. Sometimes the transphobia is relatively benign, such as inviting a trans man into an all female group or excluding a trans woman from said group. Sometimes it's someone calling trans people "disgusting," or maybe banning trans people from using the male or female restroom (or both). When all these offenses are related, it is hard not to feel as if they are grouped together in one epic fist of hate, especially when the hatred, from tiny microagressions to physical assaults, comes from almost every cis person you've ever known. Teachers and doctors and rabbis and priests, all trusted adults. Friends and lovers. Personal heroes. People on TV. Literally every cis person you have ever encountered, in one way or another, in large ways and in small ways, lets you know that they think you're a piece of human shit. I don't understand why you don't understand how some trans people can hate cis people.