Well socdems can actually improve the lot of the working class, so that isn't exactly the best comparison>b-but you can't overthrow capitalism through electoralism!
I know, but The Revolution™ isn't coming anytime soon, so we need something that will help the working class in the meantime>b-but social democracy is imperialist!
Yes, in the capitalist core, social democracies tend to engage in imperialism. However, seeing as how those countries would be engaging in imperialism either way, it isn't really a net gain for imperialism. Also, there are first world socdems, like Jeremy Corbyn, who are firmly anti-imperialist. Then of course there's third world social democracies like Bolivia, Nicaragua, and Kerala, but they would probably make your head explode.