...simply because they reply to every idea with "let's lobby the state until it's turned into a law!" Their whole idea of progress is marginal alteration of existing circumstances using bourgeois legalistic means encapsulated within the state, rather than creating working-class organization and solidarity against capital. Simply because social democracy is not opposed to capitalism, social democrats will never have the revolutionary willingness to throw aside old modes of thought. And as long as a country has social democracy, people will settle for faux socialism and real change will be put off.
These people do not examine history from a historical materialist perspective, are openly hostile to Marxism, oppose revolution, ascribe to great-man theory, make apologetics for exploitation and imperialism, ascribe to black-and-white morality, and are actively reactionary.
They serve the function of preserving and legitimizing the status quo. They are the opponents of the Socialists and we have somehow let them in our midst. I absolutely do NOT understand the attitude in this subreddit that Social-Democrats should be regarded as comrades as, at the same time, they actively steer people away from the objective study of history and Socialist praxis.