Some people are just stuck on stupid!
I can't document this, but I suspect that the position of many unrepentant Marxists is that the only reason that Marxism has failed historically is because it is necessary for it to be applied globally before it will work the way it is intended. Hence, globalism is the answer to establishing a world where the so-called inevitable stages of history as understood by Marx — feudalism, capitalism, socialism and then pure communism — can unfold.