People of mixed ancestry are especially useful since they can disconnect appearance and brain genes due to recombination. Admittedly the sample is mostly Whites, but there are more than a few Africans and African Americans (who are mixed). Here's a listing by self reported ancestry.
https://opensnp.org/phenotypes/110
Further ancestry can be determined from genotype by eg. ADMIXTURE software even if not stated.
Even if the sample is skewed towards higher intelligence, as long as variation exists between races the method will operate to determine if "discrimination" is a factor.
The sample should probably be larger, but it's getting larger.
You can enter your DNA without giving your full name I think. I guess the only downside is if you commit a crime and forensics get your DNA and match it there, and they force an ISP to trace you.