When did this become allowable?

Just wondering how many out there find that the world becoming more and more violent. I know I see and hear so much on tv and reading the newspaper is almost like reading a horror novel at times. But how many actually see a change in the amount of threatening behavior. From time to time a student will say something that just makes me stop in my tracks. And I wonder when that sort of language became acceptable. And then I have to decide if I will make it acceptable in my little part of the world. For example, I have a student who says "Shut up!" when she means No way! I have spoken with her and she is trying to stop this bad habit. Then there are the quiet threats like, You need to be slapped or Somebody needs to snatch her bald for that remark, and so many other things that people say without thinking now days. We did not force these students to to join the class. They came and asked to be taught how to give a service to customers. Part of that training - I think - is to teach them how to speak around their future customers. My teenage son said recently "I should slap you into next week." While this made others in the room laugh I was not one of them. When did this type of thing become allowable? Maybe I am just getting old but I think that isn't the issue at all. As I teacher it is my job to teach students how to handle themselves around clients and possible future clients. As a parent it is my job to teach my son respect and non-violence. Any threat of violence is unacceptable. And to say later that it was said as a joke or in humor? Wake up folks it's 2009. This sort of language is not funny and personally I don't think it should be tolerated.