Sadism doesn't fix anything. Since it's the most obvious argument I can think of off the top of my head that you'd listen to, I'll point out that there are many white Americans who are disabled, queer, etc. and they have white privilege as much as the next cracker, but if there's any truth at all to this "class consciousness" thing, both of you have an interest in being allies more than enemies.
If you want a more genuine argument, well, I do believe what I said was true so my actual take is similar, but it's that a generalized hatred for huge masses of people is effectively the symptom of a social disease, a manifestation of alienation. In general, we should seek to encourage the masses to be better rather than condemn them for not reaching our standards (however righteous those standards are in a vacuum). The left can only make progress as a democratic movement, and democratic movements must, on some practical level, believe in the people in a generalized way rather than hate them, even if it and we are deeply frustrated by the backwardness we frequently encounter.
Disclaimer: I don't mean this as a #NotAllMayos thing since I'm white, you can pray for my suffering until your hands fall off, who cares? Mostly it's that I got into a sordid conversation with some dipshit idealist reactionary on this website recently who was rhapsodizing about the glory and splendor of retributive justice and -- along with being, again, reactionary -- it just rubbed me the wrong way on a personal level.
Disclaimer 2: Fuck whoever does the "single issue voter" line, obviously