The concept of "Permanent Revolution" is failed theory to begin with, while Marxism-Leninism is not.

Secondly, the reason most Marxists have problems with Trots, is because Trots descend from the Menshevik "Left" Communists Lenin railed against in "Left"-Wing Communism, an Infantile Disorder. They tend to focus far more on purity than results, and thus are the source of countless splits and left-infighting.

Trots generally oppose AES as well, meaning they play into the hands of Western Imperialists, rather than supporting the Global South against Western Imperialism.

Trots are better than liberals, social democrats, and so forth, but there is good reason they are basically only found in the West, while Marxism-Leninism dominates most of the world outside the West, among Marxist strains.