Actually it isn't, really. Leftism, where it is not calculated evil, is mental illness.
Yes, you are right but I respect the mentally ill much more than Marxists. Even the extremely evil “holders of the puppet strings for the useful idiots’—are mentally ill because their worldview is so removed from reality with such bizarre concepts of human nature that is defies all logic and reason. Ayn Rand talks about this irrational philosophy and nails it.