The thing is, you want to frame the discussion in terms of solidarity of the oppressed. Which means, it’s a valid complaint that class issues are not being discussed, but it’s terribly misguided to try to reduce other forms of oppression to special cases of class oppression. Racism and sexism and so forth are used to divide the working class against itself, and you have to make it absolutely clear that you’re willing to make sacrifices for the sake of a united struggle, or no one can trust you.
And of course, you can’t trust the middle class, as such, because betrayal is the social role of the middle class. (Which is not to say that individuals can’t be trusted – but see, again, that bit about sacrifice.)
