I think Sarah's right.
Some people feel such a reflexive fear & disgust over someone breaching social norms that essentialize a sex/gender binary as immutable, they completely loose it and become obsessed with annihilating people who elicit that fear & disgust.
People get hung up on anything that challenges their sense of "normalcy" & "propriety" around sexuality & gender, and cis people's reflexive disgust toward trans people is driving their will to exterminate us.
https://thegoatery.dyndns.org/display/8a89e8f8-1766-9f84-222a-e75392376210