Probably true. But FB does ban outright leftists.
I would think that as long as outright leftist were polite they could post here. The problem is they so quickly degenerate into foul mouthed, ad-hominem attacks and outright lies.
They are not used to having their faulty world view challenged and being intellectually fragile, lash out and start whining.
It is, I think, behavior not POV.