Knightfall
Know Nothing Newbie
We already have that standard: unbridled, full-throated debate in a free and private society, where the line is drawn disallowing the government or courts from interfering.
As for a store run by an open racist or members of NAMBLA, assuming no public accommodations laws are violated or crimes against children committed, private citizens alone are at liberty to patronize such businesses or not, thus determining their success or failure.
Obviously, we should keep the government out of regulating free speech, but my concern is how individuals should act in these situations. I don't think it is healthy for society to try to fiscally punish those they dislike. For instance, I don't like that some people are boycotting Duck Dynasty over Si and I don't like that some people will not go to businesses promoting gay rights. People clearly have the right to do what they want, but it doesn't seem healthy to me to be vindictive against those you dislike.