Not just tankies. Try telling a social-justice type that the only identity you give a shit about is class identity. It's hilarious.
I might be a social-justice type, then. Class reductionism is appealing in its simplicity, but I don't think it's very productive. Like, it's fine to focus on a particular thing that you care about, but being unsympathetic to the things that others struggle with isn't going to garner sympathy in return. I see the parallel that you're pointing out, but I don't think it's the same.