You're not wrong. But would you rather spend your Bitcoin on merchant who discriminate incoming Bitcoin (usually also with little explanation/transparency) or merchant who doesn't do that?
I get your point, so my answer is that, as long as they accept it, I don't care if they discriminate my coins.
But if they don't accept it, then yes, I 'd rather choose merchants that do. In fact, I am obliged to do so.
The thing is, if merchants choose to believe what the governments say and start filtering coins, then we 've lost. All of us.