Bad words are bad because people decided that they are. But this doesn’t make them any less “bad.” If I use a word that people consider bad because it is “bad” , then I can’t claim as a defense that the badness is not intrinsic to the word. It doesn’t matter. I was trying to do something bad, which is bad.
Which is exactly what cursing is. It is an attempt use bad words because they are bad. That they aren’t intrinsically bad is irrelevant, as is the fact that they are only bad because people have decided that they are.
There is also some dishonesty involved. If I really and truly thought that swear words were just words, just sounds, and that calling any word a bad word was silly, then I wouldn’t be using these “bad words” as swear words because I would consider that whole concept silly. In such a case, it seems like what is really going on is a person trying to justify continuing doing something that they want to do by saying that there is no possible reason to do it. If they are just words, why the hang up on trying to get away with using them? Use different words.