Pointing out that many SSC commenters believe in “human biodiversity” should not be controversial; neither should pointing out that this concept is just a thin coat of paint atop “scientific racism.” What should be controversial is people mourning that community as some sort of valuable place for discussion.

I disagree with your characterization, but I guess the real question is whether the beliefs of some members should negate the other positive values of the community. The value I found there was that there was genuine conversation between anarchist law professors and self-proclaimed social justice warriors, anti-abortion Catholics and trans activists, Trump supporters and Trump haters, global warming deniers and global warming scientists. I disagreed with the vast majority of what people said (on all sides of all issues!) but derived tremendous value from hearing what people believed in their own words. There are few places on the web where people who have serious disagreements about culture war topics can have can have productive discussion, and SSC was one of them -- thus I mourn its loss, and actively seek a replacement.