They also killed lots of unrelated people. Let's not take the argument far enough to claim that everyone who was ever killed by socialists must have been a socialist, too.
Perhaps the author of the article is a rationalist, too. He certainly knows too much about them, cares too much, and the fact that he criticizes them only shows that there is some infighting among them.
Perhaps the author of the article is a rationalist, too. He certainly knows too much about them, cares too much, and the fact that he criticizes them only shows that there is some infighting among them.