By class traitor I don't mean a fed or infiltrator. You don't have to go out of your way to denounce leftist ideas or stop the left. You just have to have class interests directly in conflict with workers and the poor. You can let your factory unionize, and take less money. But would you choose to be that factory owner if it meant your current situation improved significantly?
I don't know what I would choose because I have no hopes of owning capital. I would love to quit my job and be free to just own stuff and make money off it. But then I would have to reckon that with my beliefs. I guess you could just accept you can't be a leftist and volunteer for the wall should the day come.
you don't get a choice, that's the point. to act against your class interest as a petty capitalist, you would have to become personally invested in a project that is larger than yourself, on a deeper level than internet fandom, slumming, or abstract fantasizing. what that looks like in practice is completely losing your mind and rejecting practically every other feature of your existence that makes it coherent.
you see plenty of people in liberal strongholds try and fail, and the point they ultimately arrive at is making moves up until their guilt is assuaged (usually charity work or public self flagellation), because the guilt is the only facet of the reality of capitalist exploitation they have any real sense of firsthand.