Hmmm, interesting on the quote thing.
But my reasoning still stands, as another example...
say you have an adult section of a "family" site (for instance) and in that adult section you had the "dirty joke" forum and only allowed verified adult members access (let's forget the logistics of verification for sake of argument) if you apply censor words in the CP your dirty jokes wouldn't be so dirty!
This could be an extension of the forum permissions system at least for the forum level.
The censoring of PM is unnecessary IMO.