It's only the appearance of social-democracy that matters in Europe. It doesn't matter which party is in power, as long as policy is broadly neo-liberal and not too aggressively anti-corporate.

When someone like Jeremy Corbyn appears and challenges or threatens that consensus, you immediately get a determined media campaign to smear and undermine him - while barking mad racist demagogues are treated as serious political representatives without being questioned or challenged in the same ways.