Self-identification matches GAT results - does this disprove idea race is simply a social construct?

If self-identified black people on average have a large proportion of African ancestry and self-identified whites usually have less than one percent African ancestry (and the rest European) doesn't that disprove the 'race is simply a social construct' idea?

The average African-American genome, for example, is 73.2% African, 24% European, and 0.8% Native American. The average white American has 98.6% European ancestry. So, self-identification overwhelmingly matches GAT results.