You could look at it as a natural consequence of the left's stated goals of social leveling, public participation in the political process, etc. But there are other ways to look at it. For example, you could view the fragmentation of, say, basically the entire Trotskyist movement as the natural consequence of wanting to dominate a political space (even if the political space is a clique-ish, subcultural & largely insignificant one, which I would argue is definitely the case in the stated example) Political fragmentation/factionalism can also be observed in fascist groups, religious extremism & cults, and presumably it's not the result of egalitarianism or anti authoritarian principles in those cases
The PSL's mindset is typical of tankie discourse, but a little more polished. Basically in this model 1) the USA as imperialist top dog is the chief agent of reaction on the world stage, basically serving the same role as England did during French Revolution-era Europe, and therefore 2) anything that potentially serves the USA's political/economic interests must be bad, while anything that potentially harms those interests must be "good", or at the very least shouldn't be condemned without qualifications.
This could be seen with their commentaries on figures like Qaddafi, Mugabe, etc.
