The word ‘race’ (and the accompanying notion) particularly bothers me; but I have little problem with the term ‘ethnicity’, and none with ‘ancestry’ or ‘culture’, and I think these can be happily exchanged with the word ‘race’ in most conversations. These three — ethnicity, ancestry, culture — are distinct and yet obviously related, and tend to serve us far better in a nuanced conversation about humans and society than ‘race’ does (of course, this is assuming we desire a nuanced conversation..). I’m defining ‘race’ as ‘social groupings of humans defining essential types of individuals based on perceived traits (to closely quote the Wikipedia article).
If I talk about myself, I can talk about my culture (something that we are born into, but that can also be consciously and subconsciously adopted during one’s lifetime) and my recent ancestry (which one can trace with genealogy), and to a fuzzier degree I can talk about my ethnicity. In my case, ethnicity is some combination of British (Irish/Scots/English), and going back further probably Pict/Norse/Roman/etc, and going back further who knows what groups? (but eventually Africa, non?). I’ve not had my DNA tested, but can be fairly certain of the main haplogroups that would be found if I did. But ethnicity/haplogroup/however we want to talk about it does not equal ‘race’, does not equal essential, defining features that necessarily set me apart from any other given human in any meaningful way.
And the way we can describe ourselves with these three concepts is far more useful than just saying “I’m white” or “I’m black”.
So, as far as “allele frequency clearly separates populations”, I have to wonder what you mean by “clearly”. I don’t think it is clear. Look at this, for example, or any similar representation of Y-DNA or mtDNA distributions, and it becomes quite clear that, though there have been more distinct groupings of people, there have not been clearly definable races.
PS. Honestly I don’t think this is really relevant to the discussion. I only included the disclaimer in my first comment so as to avoid any potential cries of “racist!” — I wholeheartedly do not believe in ‘race’, and am thus never knowingly racist (though I’m sure I am subconsciously, as most of us are..)