"Do you believe there's something wrong with blacks displaying signs that state "Black Power"
Yes.
"... and that they should be prohibited from so doing?"
No.
I can easily recognize the right of someone to do something that I disapprove of, or that I am vehemently opposed to without creating a conflict in my head.
Everyone here would probably describe me as a supporter of same-sex marriage, and that wouldn't be accurate. I am happily married to a wonderful woman, and I've been married to enough women in my lifetime that I can safely say that the traditional one man, one woman version of the marriage options is what works best for me. Yet, I also easily recognize that the fact that I belong to one team doesn't mean that I think the other team should be banned from the field. My support of one team does not automatically translate into an opposition to the other.
Except in the case of the Washington Redskins.
Screw them.
How 'bout dem Cowboys!