Shel! My thoughts exactly!
It doesn't matter where it happens. What matters is how people respond to it. Simply put, it's wrong to look down on someone for being so called "different". If I saw a child with CI picking on a child who signs, I'd step in and nip the behavior in the bud. This would also occur if I saw a hearing child doing the same to a deaf child.
And, adults? I'd put that person in their place, too!
As someone who is "different", I have seen how ugly people can be to each other and I would not tolerate such behavior in my presence no matter where it is coming from!