Out of Africa is a fact as far as the major populations are concerned as DNA studies have proven. The question isn't if the current populations of the world came out of Africa, but were they somewhere else before going into Africa.
The current interglacial period began 10,000 years ago. The last ice age was 100,000 years long prior to that. It is possible that an Asian population migrated to Africa during a previous interglacial period, say 200,000 years ago, and that's where we came from. The problem is that there are human decendents' remains in Africa 4 million years old.
Human remains 2 million years old in Asia can mean that prehumans migrated to asia from Africa, but wouldn't change the out of Africa hypothosis.
How can it be a hypothosis and a fact at the same time?