Are these sonic deterrents all that bad?

I'm 23, and I am fed up of having to walk past a shop with one of these devices because it causes a hell of a lot of pain. Imagine someones stabbing you in the ear - that's what I feel every time I walk past one of these devices. I think it is wrong to use them, especially when they affect people who are just walking past too. You wouldn't be allowed to go outside and hit a group of teenagers gathering outside a shop, so why should you be allowed to use devices like this that, frankly, hurt just as much? They're not just irritating, they're down right painful.