Are you really stating that the issues with modern society in a ultracapitalist environment such as the US is... The diversity and push to treat each human as a human and not splitting people into groups based on ethnicity or sexual orientation?

That's a very bold claim that I'd like to know more what supporting arguments you have instead of just statements.

Is the US really more "ultracapitalist" than classical Manchester Capitalism was? I have my doubts.

I'm not sure how you understand identity politics, but a diverse group of tiny sub-cultures on a "separate but equal"-platform don't create a cohesive society. There are a few points of exchange in music, food and pop culture but not much more, and any notion of assimilation gets rejected (hence the shift from "the melting pot" to "the salad bowl"). If you were to apply "divide and conquer", putting more emphasis on the differences between individuals instead of their similarities and creating lots of small groups instead of a single large one is probably a good way to create cracks.

Everything wrong with the US is exactly the opposite of what you are saying - much like every other empire before it, it is being torn down by the 'elites' which have captured and increasingly are stripping it for everything they can extract. This has nothing to do with melting pots and diversity and what not, and everything to do with a focus on short-term gains instead of long-term thinking, greatly encouraged by capitalism.

Isn't that really a particular type of capitalism (sometimes called "free market capitalism") that has been popular with politicians since the 1980s? Not capitalism in general.