Plenty of Trotskyists “become” reactionary conservatives later in life. It’s been called a pipeline. Look at Cristopher Hitchens for example.
There is an approach to politics that tends to destabilize groups by encouraging factionalism.
There is a strong tendency to view Trotsky and Lenin as basically infallible. A cult of personality. And a very selective reading of Lenin, based mostly on the works of Trotsky, to insist that Trotskyism is the true heir, the true continuation, of Leninism. Which is (a) not accurate, and (b) kind of an irrelevant point to make anyway, unless you believe Lenin was infallible and a “great man” in the first place.
There is a rejection of “socialism in one country” in Russia by Trotsky which leads to a rejection or even opposition of all “actually existing” socialist states. This results in Trots often becoming the allies of imperialism since any actually existing socialist state is a “de generate” (this word gets filtered, but I think the usage here is correct) socialism that should be resisted.
There is something in the water of Trotskyism that means it almost exclusively appeals to intellectuals and middle class folk or even upper class folk looking for a bit of edge. It has only weak relationships with socialist labor movements.
There is a nexus between the founding fathers of neoconservative ideas and Trotskyists.
There’s a certain compatibility between the Trotskyist idea of permanent revolution, the opposition to the development of socialism in stages, and imperialism.
There’s a reason Trotskyist groups are largely tolerated in the west while other groups get shutdown, often violently. They are the tolerable resistance that oppose the enemies of the west anyway and don’t do much.
But most damningly, they always try to make every protest about themselves somehow. They’re annoying.


where I ranted about them at length:


