I never know what to do with threads like this. I'll just ping a few.
The presentation is confusing and I don't see where the case is made.
The hominid progression up to ergaster is still in Africa. As I read this article, two researchers are saying that ergaster, a thing younger and more modern than habilis but slightly older than erectus, could have evolved in Asia from some earlier out-of-Africa migration and spread back the other way into Africa. Except I don't know why you'd think so.
Or maybe they're saying ergaster (found in Africa) migrated out and had become erectus by the time it hit SE Asia. Then it spread back the other way.
The question is how you explain having ergaster in Africa and the only slightly different and later erectus all over the place. Occam's Razor says to keep it simple until you need to get complicated.