> They've conditioned hundreds of millions of people in the developed world to regard the mass slaughter & genocide of left regimes in the 20th century as dramatically less important, and not fundamentally evil, versus what the fascists did.

While there certainly are tankies (aka people who worship Stalin, Mao and Tito) as part of the Antifa, they are by far not the majority. In fact, many left-libertarians despise the authoritarian tankies as much as every other educated citizen.