The right to freely trade is a basic right, as is the right to refuse!!!
I'm not sure about the right to refuse. If you refuse to give service to someone, for example, because they're black, that's discrimination and a crime in certain jurisdictions (it should be everywhere).
Are you serious??
Can you imagine.....
excuse me sir, are you refusing to take my money/coins??, I will see you in jail sir because holy hell you not buying from me after you met me is down right illegal!!!
If I go to a shop and I want to buy something, and they refuse to take my money because my skin is black or my cash looks too 'dirty' to them I would definitely make a case of this. This is a crime where I live and in most places I know, for good reason. It's a slippery slope once merchants start to do this and discriminate coins based on the history linked to it. What if my coins are linked to something controversial like wikileaks or piratebay, or other things that governments or the people with big money don't like? Won't Bitcoin become the same then as VISA/Mastercard as they can just block me from using my coins in most places when my coins are linked to any of these things? No thanks. Messing with fungibility is messing with freedom, period.