I already checked the book where the quote is from and it doesn't say when he participated in the election. At least I didn't find it but I can only assume it was before 1921.
I guess bourgeoisie does technically refer to a ruling class in a capitalist society but it's so commonly used to refer to just a ruling class or just who owns the means of production in general conversation that my usage is more colloquial. Like I would also refer to a monarch and the royal family as the bourgeoisie while the society isn't capitalist.