"Stalinism" largely refers to "Socialism in One Country," which won out democratically over Permanent Revolution. This proved correct, socialism was solidified in the USSR, and Trotsky's bitter jealousy turned him towards organized terrorism against the Soviet Union, and calls to overthrow the Soviet Union. Trotsky is the epitome of a wrecker. Stalin was never a collaborator with imperialism, unless you mean allying with the imperialist west against Nazi Germany in the Great Patriotic War. You're not going to find me finger-wagging siding with the West against Nazi Germany, that was absolutely the right move.

Yes, Trots that uphold Trotskyism when the peasantry is increasingly phased out in favor of industrialized agriculture are indeed silly. Trotskyism's relevance was in the theoretical debates in the early Soviet Union, then proven false, and should have been forgotten then and there. Instead, it survives in the west, as it serves as an anticommunist form of Marxism. Western Marxists love purity and martrydom, but hate real revolution.

Trotsky predicted nothing correctly. Trotsky predicted that the peasantry would turn against the proletariat, which was the sole basis of Permanent Revolution. The liberalization under Gorbachev was not an inevitability. Deng's reforms were not a betrayal of socialism, either, they stabilized growth while maintaining socialism.

Trots are, in theory and in practice, "left" anticommunists. They are useful for imperialism as they promote the anti-AES narrative among the left, harming solidarity and siding with the global north against the global south.