If we’re trending technical in our etymological taxonomies, then the X-words are all slurs because they insult people for belonging to specific groups. As you say, profanities and blasphemies need to address the sacred in some disrespectful way. I believe that leaves… curse words and expletives as the remaining categories of naughty words. Any others? I suppose vulgarity and obscenity, but those feel like subtypes of expletives to me.