Well, Orthodox Jews were never known for their fashion sense.
Okay, what this thread has produced is not a single reason for the white hats, but several reasons and several different hats. I’m going out on a limb to say that ALL of these hypotheses are true.
Odd that this should come up because every time I see the clip, first thing that comes to mind is to think of the guy standing right behind MLK as that ‘Pizza Delivery Guy’