I believe they’re represented in the photo by the man in a white shirt in the top right corner who isn’t paying attention to anything. Kind of on the nose, really.
(Which is a somewhat uncharitable interpretation, he could be looking away in disgust or just happen to glance away when the photo was taken)
MLKs letter from a Birmingham jail is a good take on the white moderate in times of inequality. Order matters more to some than Justice or even the law itself. Their inaction is the apathy that the aggressors can pave over in an attempt to look like a larger group than they are.
Every time I read it (not that I'm doing it monthly or anything) I find myself really impressed not only by his wisdom, but by his ability to express it, plainly, for any who care to listen.