Is this supposed to be funny?

As I was teaching today I was reminded of something I really, really can't stand. Not just one, but many students wear shirts to school with a negative message on them. Now, I get that they are supposed to be humorous, but I just don't see how these shirts and messages strengthen the family and build up the child. Here's some real life examples I've seen.
"If I see it and like it, you buy it - any questions?"
"Sister for sale cheap"
"My parents are clever, but not as clever as me"
"Spoiled Brat"
"If you don't like my attitude then stop talking to me"
"I'm not trying to be difficult, it comes naturally"
As we live in a society where we complain about loss of family values, I just wonder what messages we are sending to our children. When we buy clothing like this we (their parents) are saying it's okay to have attitude, it's okay to be negative about your sibling, it's okay to be in charge of your own parents.
Think about messages you've seen on shirts. Do your own kids have clothing like this? Why? I'm curious. What kind of child do you want your child to be? Are we just buying into the message that kids have attitude so we'll just go with it? Or, are we striving for something else? The kids we raise are our future adults. They are decision makers. It is our responsibility to bring them up the best we can to help them become the best they can. The next time you are looking at graphic tees for your kids why not get one like one of these? (also ones I've really seen):
"Awesome"
"Smile"
"Dream Big"