Give thankhs for the reasoning Eja...
I wouldn't say a theory is there to be believed or disbelieved, I would say it is there to be evaluated based on the evidence currently available. A theory is only intended to be a possible explanation for something that fits with the evidence currently available. From the evidence I've looked at so far, and the level of understanding I have of it, it seems to me that there is more evidence to support the 'out of africa' theory, than there is to support other theories.
As to the specific questions of whites' "right" to "repatriate" to Africa, and of sexual relations with whites, I don't see how the "out of africa" theory being true would necessarily affect either issue.
People whose ancestors voluntarily left a place 80,000 years ago cannot reasonably be said to have an equivalent claim to that place, as people whose ancestors were involuntarily forced away from that place a mere few generations ago. Self-proclaimed white rastas can go on about their "right to repatriation" all they want, but the idea is still ludicrous regardless of whether or not their distant (80,000 years ago) ancestors were from the African continent.
As far as dealing sexually with white women, my personal choice not to do so has nothing to do with thinking that they are a different species or anything like that. I simply recognize that in this world as it is, where Black folks are put in a subordinate position to whites worldwide, it is important for us to stick together as Black people, and big up one another as Black people, instead of bigging up the white system that busy biggin itself up the whole time anyway, at our expense. Sticking together in every way possible which obviously includes sex and reproduction. I got a white parent, and much love to him, but I don't want my children to have a white parent. The less chance of your child growing up confused about her or his identity in this dangerous racist system, the better. So my decision not to have sex with white women is more to do with the realities of the system we live under, rather than an abstract sense that it is always wrong for two people of differing "racial" appearance to have sex with one another, or even that it is always wrong for people classified as 'Black' and 'white' to have sex with one another.
To re-state my original point: I wouldn't say I 'believe' in either the Out of Africa theory, or any other theory about the origin of modern humans (other than believing in the general framework of evolution, which has been pretty well established, to my mind). It just seems pretty plausible based on the evidence I've seen, more than other theories that I've heard about. I'm not saying it's "the truth." Which is the difference between advancing a theory (always subject to modifications based on new evidence/new ideas), and making a statement claiming divine authority (as the Torah/Bible-writers did when they stated that the Hebrews were divinely ordained to murder the Canaanites and take their land).