"Cool" t-shirts for kids

I'm just not sure what some parents are thinking when they buy t-shirts for their kids. I mean how can these t-shirts possibly be a good thing? I understand that they are trying to be cute and funny, but it still doesn't make sense to me. Kids, and people in general, often live up to what is said about them, so are these the kinds of things we want the kids to live up to? We want kids to not listen? And then to think that is funny and cute? We want our kids to think that they only have to be good if there is bribery involved? Not to mention that even if these t-shirts were ok in general, they should only be for older kids. These shirts are made in sizes for kids in early elementary school! Whatever happened to nice butterflies and flowers or footballs and superheros? Aren't those things more appropriate for 5 and 6 year olds? Why are we encouraging our kids to grow up faster than they already are? I just don't get it.