Accepting the concept of biological races does not at all imply being in agreement with the alt-right, your source also demonstrates that only half of anthropologists believe in distinct biological races.

Even with the societal pressures and post modern garbage infecting science in the west 50% is a high number. In Asia and in Eastern Europe anthropologists believing in distinct races is much higher.

How many would believe that there is a systematic agenda to displace Whites in America and Europe? Or that there has ever been such a thing as a pure European? If you could find even one I'd be surprised.

He never once said he believed biologists were alt right supporters. Maybe there are some nobody knows. This a strawman.