I'd say "shameful" is about as strong an adjective as there is. Much strionger than "disgraceful" - it's quite possible in the same sentence to admit that something you did was "disgraceful", and go on to say you are proud of it. You can't do that with "shameful."

I think shameful is the right epithet in this case.

And no, it doesn't "work", Gervase. Any deterrent effect is liable to be outbalanced by the other effects, generating greater violence and more effective organisation of that violence in response. It might work with football hooligans (possibly), but a whole different set of factors are involved in this kind of situation, most especially where an army of occupation is involved.