This is a good question... however, the point is moot. Not all people from marginalised groups are disadvantaged, and not all economically disadvantaged people are from marginal groups. This leaves us two roads to travel - either we can listen to the views of self-identified marginalised groups to resolve their individual concerns and we let them battle it out regarding who is the most oppressed in a zero sum game. Or we reduce economic disparity.
The identity politics movement is falling apart because it doesn't take into account economic disparity. Whilst you can be homosexual or trans and poor for example, these aren't the voices making it into the public discourse. It is usually the middle class and above who are initiating change on behalf of their community. This wouldn't be a problem - but often those people do not see economics as a factor - as a result they frequently demonise the working class as 'ignorant' - something which generally moves the working class from the political left to the political right. This means they're voting against their own economic interests - but concordant with their own values and beliefs.
The quickest way to change the hearts and minds of the working class is to stand alongside them - see the 1980s somewhat unusual alliance between the LGBTQ+ community and welsh coal miners. The 2014 film 'Pride' does this story a great deal of justice. When the Labour Party moved away from the economic argument and into the minefield of subjective middle class oppression - it moved away from power. That will cost LGBTQ+, Black and Trans people in the long run because the right will hold power. It's happened here in the UK and if the US isn't careful you'll see Biden et al swept away by a centralised right wing Christian and a democrat party that won't stop bickering about different styles of subjective oppression for a generation. That's the legacy of identity politics.
Apologies for the lengthy reply - but it really cuts to the heart of how I think the middle class left is failing minority groups.
