Lack of compelling statistical evidence that explicitly shows otherwise when taking into account different environmental and societal backgrounds.

Sure that is a nearly impossible to accomplish considering how convoluted this equation is so we have to step back and it becomes a question of belief, and in this world of belief I can really only condense it into two categories.

1. If it exists, it doesn't matter 2. It exists and does matter ("does matter" in my mind precludes equality, one must be superior)

To me it is really a question of whether I personally choose be racist or not, racism being defined as "prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior".

I'm going to cut this short at that I do not believe someone can both believe a specific race is superior and act without prejudice. Again a lot of assumptions, but if wanted to keep going down the ladder of explanations I'd write an essay or a book.

I'm referring to things that affect ability (things like skin color are different but not unequal in this regard). Even if certain small communities had some variations they become meaningless once you reach the scale of "asian", "european", or even just "chinese" so once your are talking about a group of any significant size it averages out. I used the term "necessarily" because by statistics on that large of a sample they will be equal unless there is a reason to think the underlying distribution between those groups is different (which I don't think there is on a large scale).

I'm skeptical. There are clear physical distinctions between different races. Africans clearly have blacker skin, a different facial structure, and different hair types compared to Nordics.

Unless one is going to argue that there are no genetic differences between individuals in the brain, it seems unlikely to me that different races don't have different brains in some fashion.