Says you.
He illustrated evolutionary distance to those ancestors. He did that specifically to make his point about how incredibly uniform we are as a species.
He talked about two distinct "Out of Africa" migrations. The first, Homo Erectus, a little over 1.5 million years ago, who left Africa and colonized Asia, Europe, and definitely Indonesia as well. (Now extinct).
The second migration Dawkins said was extremely recent, less than 100,000 years ago. (Reminiscent of what seems to be showing up in the Trinity research data of Dan Bradley and Bob Quinn's investigations in his documentaries that I sometimes post up for interest.)
He then talked of human genetic uniformity saying if you look molecularly at the molecules of modern human races, we are astonishingly uniform.
He pointed out that such genetic variation as there is exists mostly within Africa.
He said this suggests that the deepest divides of cousinship in our species are within Africa itself. While the whole of the rest of the world is "a very, very recent branch-off of the human species."
He said if you look at the amount of genetic variation in the human species, it's extremely low. He said if you take two chimpanzees from the same forest in Africa, they are likely to be more different from each other genetically than any two humans in the world.
He finished by noting how surprising this may be to people less inclined to abstract thinking like yourself when you consider that races look so different to our eyes.
But he emphasised that the genetics is very clear - that we are an astonishingly uniform species, that we are all one species, one very uniform species, and we originated very recently in Africa.
And that is exactly what he said. And he wore the t shirt to emphasise his words.
Also noting Dawkins goes further in acknowledging these tiny inter racial differences than most of his scientific peers who say they are too small and scattered across "racial groups" to be significant - who emphasise that "... no group of people is, or ever has been, biologically homogeneous or “pure.” Furthermore, human populations are not — and never have been — biologically discrete, truly isolated, or fixed. Genetic and phenotypic variants are not distributed across our species in a manner that maps clearly onto socially-recognized racial groups. This is true even for aspects of human variation that we frequently emphasise in discussions of race, such as facial features, skin color and hair type..."