It should come as no surprise, but ESPN commissioned a poll about the anthem protests. Top line numbers:

Strongly Approve: 24
Somewhat Approve: 15
Somewhat Disapprove: 13
Strongly Disapprove: 38

When you break those numbers out by race:

Whites: 17/14/14/48
Blacks: 54/18/7/9

Also of note, 53% believe Kaepernick would still be in the NFL if not for his protests.