Why do regressive leftists always talk about race?

I think many leftists are mentally not capable of treating people as individuals instead of by their group memberships.
"You can't paint with a broad brush" is a valid response if someone is painting with a broad brush and if you then go into the specifics of what people do/believe.
But they use that term whenever a member of a group that does poorly is criticized.
So maybe they honestly view that as a criticism of the whole group and they're not able to mentally separate that individual from their group membership.

The only time they criticize a muslim is as a member of another group, separated from other muslims: extremists. So by separating the bad elements out of islam, the remaining muslims are all good. Note that after separating the extremists out of christianity, the remaining christians are still bad. For wanting religious statutes, not wanting to pay for your abortions or birth control, any christian religious motivation is seen as bad. So their argument that it's only the extremists that are the problem isn't even valid, because with christians they're all part of the problem.

And with the Google memo firing they've shown that even in the face of strong scientific evidence they absolutely CANNOT accept differences between groups.

Of course we don't see a problem with that because there would not be bad consequences to that. Because we will still treat individuals based on the content of their character and their actions.

So maybe it's a mental deficiency on their side, that if they would accept there are differences between groups what would they do?
They would probably have to admit to treating people based on those group memberships (even though they already do that). But right now they're able to excuse that special treatment as compensation for the differences in outcome that group has in society.

So they're desperately afraid that admitting there are differences between groups will turn them into Hitler.