Trannies have autogynephilia, a mental illness where one is aroused by self-inserting as the opposite sex. However, they don't actually want to be foids at their core, this is an illusion.
It is related to severe forms of body dysmorphia which cause people to cut their fingers and limbs off.
It is also related to covert narcissism, at least regarding the "blurry or absent sense of self" as vaknin describes it (this is often seen as a metaphor, it is not).
In an environment which breeds maladaptive non-grandiose narcissism and general dysphoria/dissociation, blurs or deletes the psychosocial line between "real" and "online" (see: Lain, The Matrix, and how they are now regrettably beloved by trannies) and gives children access to personally curated porn, while simultaneously raising a generation of young american men with the least "to lose" in a long time, with no outlet for aggression thanks to "safety culture" and the demonization of mutual combat in young males, it was almost inevitable.
Literally forcing it down people's throats may not have even been necessary, but it was certainly the 150 kiloton panamax container ship that broke the camel's back.