Without getting lost in the weeds of quibbling over semantics, racisms seems perpetuated by a need to identify oneself with a particular group. Race/Ethnicity Self-Identification forms seem obtuse. The Census Bureau says it uses the information to conduct research to “improve” questions and data on race and ethnicity.
In my opinion, race is primarily a sociopolitical construct. The sorting of people into this race or that in the modern era has generally been done by powerful groups for the purposes of maintaining and extending their own power.
Biologically speaking, we are all mixed. That is, we all have genetic material from a variety of populations, and we all exhibit physical characteristics that testify to mixed ancestry. Biologically speaking, there never have been any pure races — all populations are mixed.