I think there is a lot of stuff that people say DFACS will take your kids away for, but they are wrong. I mean, if DFACS took kids away for stuff like that, why are there kids out there that are abused and beat to death? I don't think a little vinegar or hot sauce would hurt your son, but I don't know if it will help either. Most kids continue this kind of behavior because they know it will get a response. If you just don't react when he says the words, he will probably stop sooner than if you put hot sauce on his tongue. And he is at an age where he will repeat anything he hears, and he is experimenting with different words, so if he gets a reaction out of you about these words, he will say them just to get the reaction.
By the way, we put hot sauce on my now 17-year-old daughter's thumb because someone had told us that would make her stop sucking it. No luck, she loved the taste of the hot sauce. So she tells me that she still sometimes sucks her thumb if she is really upset or if there is a thunderstorm at night. I can't understand why, but I guess it won't hurt her.