Earlier quoted context omitted.
What if the race is synonymous with a religion- Judaism and Jews being the obvious example?
Except it isn't. There's a clear distinction between Jews as an ethnic group and Judaism the religion. Hence frequent criticism of and among various Jewish movements without it being anti-Semitic.
This also shows in how Israel regulates its immigration: both people with ethnically Jewish roots (at least one of your grandparents) and people of Jewish belief where ethnic roots hadn't been established at that time (biggest example: Ethiopian Jews) are accepted and granted citizenship.
Conversion of people to Judaism are relatively rare, and are really a more recent phenomenon. Jews don't proselytize and often discourage conversion. Samaritans, the "sister" religion of Judaism (both derive from the Israelites from before the destruction of the first temple), are similar but even more extreme in that. How more tribalistic than that can you get?