When I was a kid and filtered the world as facts in black & white, it was baffling why certain words were "bad". Why is c_nt so bad? That doesn't make sense -- It's just a word! If you were to let a foreigner who didn't understand English listen to 100 random words with c_nt being one of them, he/she would not be able to identify which word was the nasty one. Listening to the phoneme is not enough. With that mindset, I laughed along with the George Carlin "7 Dirty Words" routine[1].
Later in life, I ran across across a thread discussing profanity and I saw an interesting sentence that finally made it click. Basically it said, "if c_nt wasn't the taboo word, it would be another word that was equally taboo."
In other words, we seem to always create this "space" in language reserved for taboo. It's not related to specific phonemes. If one says that humans have built in brain wiring for "grammar" (Chomsky[2]) to understand nouns, verbs, and recursive clauses... one might extend that to say we also have innate brain wiring to always create taboo swear words. It is unavoidable.
For example, the creator of Esperanto didn't put any cuss words in his language because he thought it was unnecessary. (It was a language designed to foster harmony so that's understandable.) Nevertheless, Esperanto evolved to eventually have swear words.
I notice that manufactured languages such as Klingon also has swear words/phrases. However, I'm not a trekkie so I don't know if they elicit any negative emotions or they are there simply as an exercise in "universe building".