That is what requires a deep statistical study and the PSL does not appear to give the impression that they have done so.
I'm not sure why you have this impression. You seem to not want to explain your position at all. You just make these broad claims about the party. I'm not a party member, but you can read their 2005 assessment of the US working class here: https://liberationnews.org/05-04-01-the-us-working-class-today-html/ obviously this is dated, but I have no reason to believe that they haven't continued to build on this analysis over the last two decades.
Their party program is here: https://www2.liberationschool.org/program-of-the-party-for-socialism-and-liberation/#part1 updated last in 2022. Its unclear to me If you've read either of these.
Lastly, they produced a book entitled "Socialist Reconstruction: A Better Future for the United States." Which you can find here: https://1804books.com/products/socialist-reconstruction-a-better-future. I haven't read this yet but its on my list.
So, the answer to your question of "which groups benefit?" isn't a mystery. They argue the vast, multinational working class, particularly its most oppressed sections (African Americans, other oppressed nationalities, immigrants), has the greatest objective interest in dismantling U.S. imperialism, as it would end both the super-exploitation of the Global South and the domestic austerity and racism used to divide the working class at home.
I'm not sure if "statistical analysis" is what you meant here. I'll assume not. Since both revolutions you mentioned were built on the backs of rigorous political analysis from a Dialectical Materialist world view.
You accuse them of having not performed similar work, and almost seem to imply that you know the answer that the PSL doesn't. You again are not saying anything, you are simply making claims that you are not backing up with any sort of personal analysis from what I can tell.
And its not that the PSL isn't beyond criticism, but I'm not even sure what your criticism even is to begin with.