I think since it's an MLK tourney, you have an opportunity to use that as part of your pre-game. I don't see anything wrong with making mention of it...The fact that I'm white doesn't really play into it to me, cause if MLK were lining up for the tip, he'd be ok with me reffing!
On the question about peaceful protest....I guess I'd have to see the action leading up to the sit in....