First off, no, I'm referring to (at least some of) the parties I listed earlier as Hindenburg's base as bourgeois parties. I suppose you could include the Nazis and the SPD, but that's not how I'm using the term, note that I said "the bourgeois parties... [and] the Nazis who they collaborated with," implying a distinction.
Second, a bourgeois party is a party representing bourgeois interests and receiving bourgeois support. Working class people can and did support bourgeois parties, though as history showed, they shouldn't have.