The American people have failed? Shamwow? Such dramatics Is this really what bothers you so much? The degree of distaste you have of this is disproportionate to its required criticism.
It's more so similar to Obama appearing on a radio morning show that does comedy while hosting guests, which politicians have done for ages as well. I, for one, am perfectly accepting of a high stature politician appearing on The Daily Show or the Colbert Report. I think they are of higher quality writing than Leno's staff, but it's nearly the same idea, isn't it? Are you that out of touch or that cranky that you can't relax for a few minutes?