We should not forget that socialists and others on the left wing have succeeded in killing well in excess of 100 million people in the past century. Sure, they sound like idiots when they spout this crap, but don't ignore their success in delivering on their threats.
I’m surprised that people are surprised about leftist bloodlust.
You would be hard pressed to find a time in history where the left attained total power and did not exterminate their political opponents and those that dissent.