This attitude towards the problem has always struck me as counterproductive. It's true, of course, that everyone has biases, but it's possible to address those biases without putting such a strong emphasis on their permanence. (I won't go into whether or not they are permanent here.) That emphasis seems more likely to create a self-fulfilling prophecy than anything else.
I'm only speaking from personal experience, of course. Take it as you will.
Any individual sexist practice isn't fundamentally permanent, but because of time constraints, some will turn out to be, in practice.
I think it's counterproductive for people to shift attention onto the things other "real" sexists/racists do, rather than Do Their Own Work. That's why it's productive to point out that everyone has work to be done.