Among the general population of working scientists, Lewontin is “best known” for his groundbreaking contributions to evolutionary biology and evolutionary genetics. The circles among which he’s “best known for his fallacy with regards to racial divisions” tend to be those of scientific eugenics and lay racism.
His Wikipedia page mentions his anti-determinism work/activism in the introduction section too. :)
You can also look at his citations: https://scholar.google.dk/scholar?hl=en&q=lewontin&btnG=&as_sdt=1%2C44&as_sdtp=
His #1 citation is his famous paper against the adaptionist program, i.e. part of his anti-determinism work. His #2 fits what you are saying. His #3 is again part of his general behavior genetics/differential psychology denialism. #4 concerns the very question of how to apportion human diversity. #5 is his communist biology manifesto (didn’t we try that once before?). And so on.
You can also look at his publications the last 10 years, they seem to be exclusively or mostly about his denialism project, i.e. political activism. He states this himself in his own books. See also Defenders of the truth.
So yeah, he is mostly known for his political activist biology. He did some real work a long time ago, for which he is still rightfully known to population geneticists.