On the off chance that anyone pro-idpol is reading this, please give it a chance and let me explain my reasoning before you put me in a box of being a 'brocialist'. I will admit not being as familiar with the work of intersectional theorists like Crenshaw as I should be.
Also mandatory identity signifier: I am straight, cis, and male, but I am a mixed south east asian/white and a few other things person. I look like an ethnic version of mclovin from superbad ate too many 3am burritos on his way to his 30s, but i digress.
These are my thoughts.
Here on anti-identitarian left, we dislike IDPOL. But the reasons for this are far more nuanced than are usually given credit for. The pro-idpol person reading this probably imagines that the anti idpol leftist is some white macho dudebro who is a barely reformed fashie that likes the economic parts of socialism only because they affect him personally, and doesn't have enough empathy or is ignorant of the struggles of other groups. And to be sure, there actually are some people that match that description and use 'anti idpol' as cover to be a douche. That is wrong. Racial discrimination is wrong. Homophobia is wrong. Bigotry in general is wrong. We all agree to this at least in principle on the left.
But that doesn't excuse problems with identity politics on the left.
1. Corporate Co-opting. When we see Colin Capernick getting nike endorsements, feminism being viewed positively by mainstream media outlets, etc. We can see that wokeness and corporate capitalism are not incompatible. that is not to say that feminism etc. are bad, but just that they do not challenge the system in as deep of a way. Indeed, if you look at many pride parades today its difficult to even tell that acceptance of and visibility for LGBT+ is the goal of the parade, or rather the glorification of the tech industry, as you see the marchers holding up signs that say INTEL, MICROSOFT, APPLE. You can have (and often do) major corporations endorse feminism and lgbt+ issues wheras amazon would obviously never endorse a march to increase the minimum wage or pro-union. This is the sort of "woke neoliberalism" epitomized by people such as Hillary Clinton and the tumblr crowd - The Californian ideology. Sex, Drugs, and fiscal conservatism.
This is why so many on the alt-right see themselves as 'anti-establishment' even though they are merely useful idiots for capital. Its hard for the 'woke left' to claim to be anti establishment when numerous major corporations (other than chick-fil-a and a few bakers in no-one-gives-a-shitsville, Indiana), all major news establishments (such as the Guardian, CNN, MSNBC), most univerisities, and a whole class of insufferable centrist upper middle class liberal white people who look down their nose at the working class, are ALL aligned on this issue. They are ALL functionally 'socially liberal' or at least pretend to be. This is not to say it is bad, but it is certainly not transgressive, edgy, or non mainstream in the way such positions may have been in the past.
2. Identity and Justice
Now I can hear the pro-idpol person screaming, so what, you just don't like idpol? 'fuck' idpol? so what are you really saying, fuck marginalized people? No, thats not what were saying. We have to make a sharp distinction between issues of identity and issues of justice. Take the issue of media representation. Many people for example of Asian or Mixed asian descent complain that there is not enough representation of us in media. they say "every time a diverse person is in media, everybody gets mad, are you so narcissistic that you have to see people like yourself in media?" not noticing the enourmous hypocrisy. If white people are narcissistic for wanting to only see white people in media, how are you less narcissistic for wanting to see people like you in media? and if the race of the person doesnt matter, why does it matter if most actors are white? I think we are all agreed that race is a social construct and therefore an illusion only kept real in peoples heads. However I feel like some of these people don't have a goal of actually dissolving the social construct of race. They just want to see their own identity and group celebrated. In short, they are against 'white supremacy' but not racism. They are just angry that their group for historically contingent reasons did not end up on top and europeans did. They merely want the ability to navel gaze as hard as, to pat themselves on the back as hard as white people. Its so unfair, that we aren't allowed to celebrate ourselves as hard as white people do! Which isn't even remotely the point.
Its not only that it gives license for people to indulge the most base human instincts of narcissism and tribalism, but that it lets people think they are RIGHTEOUS for doing so. My navel gazing is revolutionary!!1!
They aren't against the idea of one group being dominant over another, they just dislike it when white people do it. These people are not your friend or ally. They are merely Richard spencer with a tan. Because there are white richard spencers, but there are also brown, yellow, red, and black Richard Spencers and its only by a series of random events in history that White richard spencer ended up being richard spencer and those guys didnt.
You see both Spencer and IDPOL people agree on something that we don't. They both think whites are some unstoppable force of history, the difference is that Spencer thinks thats a good thing. In their heart they don't actually believe white supremacy can end (or at least not in our lifetimes). We should understand that white supremacy is a temporary state of affairs like everything else. Today the west is on top, but tomorrow and the day after that its anyones guess. It is only a temporary state of affairs that white europeans dominate the planet. At one point the middle east was the dominant civilization, the ottoman empire, egypt, etc. Yes white people have privilege today, but that is a contigent rather than necessary aspect of society and capitalism. One could conceive of a capitalism which is not racist as racism may be used by capitalism but does not fundamentally contradict it one way or the other.
3. Class Reductionism
Many times anti idpol leftists are accused of being "class reductionists". Meaning they prioritize class above other things. Implicit in this is the idea that they prioritize workerism and "chad" white factory workers above POC and other marginalized groups. What they dont realize is that many of the categories of gendered and racialized oppression could be reformulated in terms of class. Black sharecroppers in the south during reconstruction could be considered a class under semi-fuedal relations. A 1950s housewife doing domestic work could also be considered a class as well which Engels does.
The fundemental question is this: is class struggle the engine of history or not? If you use the formulation I gave, then it is. However if gender, race, etc. are fundementally different axes of oppression that have nothing to do with class, then history is just a series of people struggling against different opressions for different reasons at different times. The directionality of historical materialism, where the proletariat is destined to overthrow capitalism is misguided, since at any time, what struggles, if any people engage in, are determined by what lens they view the world