Troons do it because, even with how deluded and "supported" they are, they know deep down that there is something horribly wrong with their minds and that transitioning fixed nothing and in fact made things worse.
Rather than accepting they made a mistake, they dig further into the hole in a vain attempt to try and prove that they were right but simply didn't go far enough. They try to take everyone like us down because they have puffed up their egos to such a large degree in another vain attempt to cope through projecting to everyone that they are "fine" when they clearly are not. This leads to their massive inflated egos being so fragile that even the most blunted of jabs can pop them into oblivion.
Leftists do it for ideological reasons, rather than extreme untreated mental illness (most of the time). They naively believe that all of the worlds woes can be cured with whatever lefty ideology they were indoctrinated with and that things keep getting worse because they have not gone far enough. You could argue they are just as deluded and sub consciously aware of the problems with their ideology as trannies, and just as stubborn to not be wrong leading to a similar reaction to criticism.
It can all really come down to a lack of maturity and experience really. Because both groups have spent most of their lives being sheltered from all the worlds woes they have never had to engage in genuine conflicts that build character and allow for the mental development of healthy defense mechanisms. So they really are just over grown children that were thrust into the harsh world naked and have no real idea how to cope with it other than spout childish ideologies or inject themselves with drugs as a "quick fix" to issues that would take a long time to properly solve through healthier means. They also react to those who don't coddle them with tantrums, insults and other childish outbursts.
