my suspicion is that the out of Africa theory was promoted since it was more PC. Nowadays the "scientific theories" are all political.
edit: On a related note, my siblings' DNA test results say that they're something like 4% Native American, yet we have very reliable documentation of pure British genealogy back on all lines almost all the way back to the 1500s. Very unlikely to actual have a modern link. I'm sure the companies are likely overplaying the similarity more than anthropologists would, but am I to conclude that I have a closer link to Native Americans than other random samples from Europe?
It's whatever opinion/theory the person speaking disagrees with.
It's more likely that at some point in the last 15,000 years someone in your lineage had a child with someone with some Siberian background way far back.
Also, the classical meanings of terminology like "negroid" or "caucasoid" doesn't really map to genetics. My personal experience is that they're almost exclusively used by people who aren't familiar with modern understandings of human evolution. There are a lot of cranks talking about it, so it's often best to avoid archaic terminology that might get you mistakenly grouped with them.