It's also less visible. Some people are sensitive to each, but the people looking for gender differences can claim that any commenter who has a gender neutral name and stance is adding to the apparent dominance of male viewpoints. Only a few have visibly female names. (There aren't many visibly male names, but it's enough given our priors about the on-line population.)

It's harder to argue that race-neutral names and viewpoints make the racial or ethnic minorities more clearly minorities, since there aren't enough self-identified of any race or ethnicity to form groupings.

Or have I missed a significant discussion of this in some comment thread?