It's not what we, particularily, believe. It's what it empirically is: liberalism. Identity politics is liberalism 1.01. It's a way to divide and conquer the working class, creating meaningless sub-groups (be it white nationalists, black nationalists, LGBT groups, etc) to pit against each other. This goes against the principles of dialectical materialism and class warfare, which dictates that classisim is the main form of oppression that other -isms latch upon.
Ever notice how identity politics, feminism and LGBT "struggles" are very first worldist and almost exclusively a focus on the anglo-sphere and anglo-sphere influenced countries? As a matter of fact, the old left (what we basically are on Zig Forums) was/is exclusively focused on class struggle, while the so called "new left" were merely liberals pissed off about american segregation; which of course was a bad thing, but they missed the forest for the trees: capitalism was the reason why slavery and segregation existed in the first place.
Identity politics is liberalism. Third wave feminists merely took identity politics to it's absurd and logical conclusion; gamergate merely paved the way for Zig Forumsniggers to go mainstream.
Given how ridiculously invasive and disgustingly influential the US is, way too influential. Ever wondered why communist countries (venezuela, cuba, north korea) or non anglo-influenced ones (iran, morocco, etc) gives little fucks about idpol? Capitalism cannot be separated from idpol; capitalism created it to subvert the working class with great success. Nothing scares the rich more than class unity.
Idpol = bourgeois ideology that goes against working class ideology and struggles.
Exacly the way it was intended: I got mine, fuck you. Communism demands collective action against the system that oppresses the collective (working class): capitalism. Idpol demands action against a particular individual problems. Both the so called "identitarians" (white nationalists) and SJWs practice identity politics, just mirrored versions of it.
This is more of my own personal opinion; I don´t speak for Zig Forums, or even the anti-idpol left: Free speech is ok, but freedom from consequences is not granted.
What do I mean with this? It doesn't mean there should be legislation or a body of authority that regulates free speech to protect so called "marginalized" or "minority" groups. What I mean is, if you call a black guy a nigger, no one will stop you from doing so; just don't expect said black guy won't punch you in the face or beat the living shit out of you.
Use common sense. You can't always get away with everything you say. Just because you can, it problably doesn't mean you should, so use your brain.
Long-story-short: So called "cultural marxism" should actually be called "cultural liberalism", because that's what it is. Never take Zig Forumsnigger's opinions/nomenclatures as the be all, end all of philosophy and politics. They came up with a bunch of retarded shit, because they are complete subhuman morons.