It is very difficult to blacklist coins with the current culture of Bitcoin. If 1 person refuses to accept the coins, there are thousands and thousands of othe

It is very difficult to blacklist coins with the current culture of Bitcoin. If 1 person refuses to accept the coins, there are thousands and thousands of others who knowingly WILL. And an even larger group of people who aren't even going to be aware of your blacklist and will do so unknowingly. In order to blacklist coins, it is not enough to just blacklist the 1 address. You have to black everyone who accepts those coins, and everyone who accepts coins from the people who accepted them and so on. And at that point you have blacklisted the entire network.