I'm always of two thoughts when it comes to censorship regarding decency. One is, it's not needed when people have a strong sense of what they think is appropriate behavior. Some of our more vulgar comedians wouldn't generate a lot of laughs in a retirement home. When the population itself has the power to shut it down via lack of interest, or even mild outrage, censorship isn't needed.
On the other hand - a couple of thoughts - and one is, the press, the media have a unique relationship with the public in that they CAN, over time, shape what the public regards as appropriate, decent, and in some cases, what the *truth* is. So they do carry some responsibility to censor themselves, at least, in my opinion.
The other - and I can't think of a good way to phrase this - there's always one in every crowd. It only takes ONE person to do something really vulgar in public, and then cry foul when the community at large says "oh grow up, for Pete's sake". You don't have decency laws because, without them, people will drop their clothes and f*ck on the streets of DC in broad daylight. Most people exercise decent behavior. You have laws like that because *someone* WILL, and most of us don't like it.