This doesn't mean they don't deserve it. It just means you are sad it had to come to this. The fact that you had to resort to violence, due to how awful they are, means they deserved it. Had they not deserved it, you wouldn't have great cause to be violent. Unless you are becoming violent towards people that would respond to lesser input, they deserved it.
Nah, I am disagreeing with how you are using the word deserved. You earned it through your actions. If your actions mean I need to do something violent to you, you fucking earned it, therefore you deserved it. It isn't that hard.