You talk about people getting DNA tests and thinking “it explains all these things in their lives like…no wonder I’ve always been such a great dancer.’”

And go on to say “if you’re feeling a little bit offended right now, you should because that is the point. These so-called realizations that people are trying to tie back to their black ancestry are pretty much always based on the worst racist stereotypes. Stuff like ‘all black people have rythm.’”

Sorry, but how is that a “racist stereotype”? It is a generalization to be sure. But at last check, having rythm was not considered a negative trait in almost any culture. Similarly, if someone states that people of African ancestry are typically better athletes, while that may be a generalization, it is hardly a negative one, nor certainly racist. The percentages of black athletes in truly athletic sports like football, basketball, and track and field, all but makes the point academic.
So let’s take a potentially more offensive stereotype (mostly from days past): Black people enjoy watermelon. Now this is an ugly one that immediately conjures up nasty racial images in our heads. And yet, aside from the fact that racist hate groups co-opted it as means of an insult, how exactly is it a negative? What’s wrong with liking watermelon? I sure like it. Don’t you? And in the South, where it’s ubiquitous in Summer months, just about everyone, back and white, views it as a refreshing, relatively healthy treat. So suggesting that black people like watermelon in disproportionate numbers to whites (or other races) probably isn’t even an accurate generalization, but neither is it a harmful racial stereotype. Not unless consumption of melon can somehow be proven a function of ethical or moral decay (which I think is a bit of a stretch).

Ditto for physical traits like thick (or full) lips and nappy hair; which while certainly not applying to ALL black people, applies to a large enough percentage to make it an accurate generalization. And guess what? Neither trait is a NEGATIVE! That is unless you think full lips are inferior to thin ones; or that nappy hair is inferior to straight hair. (Personally I have both traits, and while I like my full lips, I wouldn’t at all mind more manageable hair).
Now there are certainly negative (and yes “racist) stereotypes out there relating to every race. The stereotype that Jews are greedy is quite negative because human beings (the ratings of The Apprentice to the contrary) view greed as a negative trait. But while the belief that Jews like bagels is a generalization (surely some don’t) it’s not racist unless you think there’s something corrupting about eating bagels.
When black people refer to white people as “white devils” that is neither a stereotype or a generalization (partly because the Devil is only a concept), but it is a racial slur. Racial because it is reserved for whites, and a slur because in a Christian society (and Muslim as well) the Devil carries some rather negative baggage. A little too much in fact to consider the term “white devil” as complimentary.

In conclusion…

You’re simply following conventional (and flawed) wisdom, instead of reaching your own (and one would hope) more profound and insightful conclusions. It’s well-worn defensiveness without an updated application of logic.

Please do better.