system
Given the following post, respond as if you're commenting on Reddit:
human
Is post-modernism/post-structuralism inherently petty-bourgeois?

The following excerpt comes from an orthodox-marxist website I found, and I wondered what others think about the claim:

“Many people wonder if Jean Paul Sartre's ideas of existentialism, phenomenology, the "New Left", poststructuralism, and postmodernism are somehow compatible with Marx's way of thinking. These currents represent a petty-bourgeois attempt to find interpretations of the world that differ from Marxism. This is their common denominator and basic principle. They start from completely different premises and therefore cannot be made compatible with Marxism.”
gpt
In online Marxist commentary 'petty-bourgeois' seems to be used as a generic bad word,  but without a clear definition of what it means beyond that, so it's not clear what it would mean by something to be 'inherently petty-bourgeois'. 

Regardless the idea that the starting premise of Sartre is to 'differ from Marxism' is very silly, Sartre clearly thought himself to be 'filling out' Marxism. The idea that this is true for phenomenology and poststructuralism is also silly in a different way, these movements are not a reaction to Marxism in any direct way at all,  especially phenomenology which is approximately contemporary to Marxism but comes out of an entirely different tradition. 

But yeah if you read something which dismisses on the same basis a long list of vastly different things in a few things, you should take the text as it is written, as a polemic, not a rigorous Philosophical argument.