It would seem, it isn't the sounds that are offensive, but the intended meaning. Although little old ladies seem more offended by the sounds then the meaning. They tended to get all offended when swears are used casually without the normal intended meaning. In any case, if it is the meaning which is bad, then switching what you say to something 'clean' should have no effect. For example, dang, frak, drek, etc. If you use them when you mean to swear, it is just as bad and should offend people. The only thing is... they don't know to be offended because they haven't been taught.
There are plenty of things which are offensive which are not regulated on TV so why a couple sounds? I'm not offended by the sounds, but I am offended by the hairy ass crack of a fat plumber. Why is he allowed on TV? I'm offended when people won't take responsibility and put things onto god. Frankly I'm horrified every time someone says they are praying to god for guidance.
My point is you can't broadcast stuff that won't be offensive to someone, so why bother 'protecting' the couple people in the world who have been taught that swear words can harm you somehow?