I think most people would find this confusing simply because it’s not a priority for them. I don’t imagine there are too many people outside the offices of Charlie Hebdo who wake up every morning and think of ways to exercise this aspect of their “right to free speech.”
That’s a good point. Even a very active Freeper isn’t going to spend a lot of time pondering his right to “blaspheme” a particular religion. It’s just not something that comes up a lot in life. Also, how many people can define “blasphemy”? I run into a lot of people who can’t even properly pronounce the word “ask”.