If players aren't prohibited from speaking, what we percieve as 'situstions', will have a way of working themselves out. Players who drop the n-word too often or otherwise make an ass of themselves are going to find they won't win as many accolades from the media, theyll get a bad reputstion, coaches will be pissed at them, and their draft stock will suffer.
Sooner or later word will get around, and players will evolve. Not all of them, but most.
Plus, prohibiting them from speaking deprives them from, you know, actually learning something. For all the undeserving praise we give coaches for "molding young men", this is a circumstance where there is an honest to goodness life skill that can be taught; how to speak up and conduct yourself in public.
And it doesn't mean a coach can't discipline a player for something he says, like cursing or criticizing officials or the coaching staff. You break a team rule, you pay the price. But the rule can't be you're not allowed to talk period. That's a wee bit too broad for me.