It has nothing to do with Cena, kids wont pay attention even if they do hear about it.
Also, just because someone is on TV, does not make them a role model. Its up to the parents to explain to their own children what is right and wrong. I grew up watching wrestling, and it was my parents that told me it was fake, and a form of entertainment just like the movies, and other shows I was watching.
This was meant to remain backstage, and an inside joke. It leaked, sure, but its still meant to be a joke. Its people like you thinking the way you do that has hindered comedy for everyone, unless you are a minority like Russel Peters.