McGrath, I decided to look up "censor" and "censorship" myself, as you apparently also did. While the Webster's definition I found is not identical to the one you quote, it essentially says the same thing -- that the motivation is repressive, aimed at limiting the free expression of the party being censored. After dispensing with the first definition (magistrates of early Rome), Websters defines "censor" thus:

"one who supervises conduct and morals: as a: an official who examines publications or films for objectionable matter b: an official (as in time of war) who reads communications (as letters) and deletes material considered harmful to his organization"

Websters goes on to define "censorship" thus:

"the actions or practices of censors; esp: censorial control exercised repressively"

Again, these definitions do not seem to fit very well with the actions of the Letterman producers, who really seem to have been doing nothing more than making creative decisions about what would work best as light entertainment on a late-night show that specializes in light entertainment (best known the gap-toothed "What, Me Worry?" expression of its host, and for Stupid Pet Tricks). "Censorship," as defined by the dictionary and common parlance, tends to mean something different and potentially much more frightening, otherwise it would not be such a loaded term. And since it IS such a loaded term, I think it should be saved for those instances where its use is truly warranted. This, in my considered opinion, is not one of them.