Why do American journalists take themselves so seriously?

I spent a nice afternoon watching the Australian version of the Today show. It is funny, the men start sex jokes, and the women raise the stakes until the men get embarrassed and wander off set. Then they joke about how the guys start stuff but can’t finish it.

I am aware that in England newspapers shows boobs in their newspapers like it is the most natural thing in the world. Why do news anchors take themselves less seriously in other parts of the world, while American Reporters consider themselves sober professionals?