It’s a generational thing. The first golf game… The first tax return… Microsoft Vista…
“We’re gonna fuck ya now, sheriff… but we’re gonna fuck ya slow.” - George Carlin
First, I think there’s two different types of swearing.
Type 1, talking about supernatural beings and (perhaps implicitly) imploring them to intervene in human affairs. Examples: Oh Zeus, give me strength. May god strike me dead if I’m lying. Damn you all to hell.
Type 2, talking about perfectly ordinary bodily functions and using vulgar words to describe them. Examples: He stepped in some feces and said “oh shit!”, so I called him a pussy.
Supernatural swearing is taboo because of the belief that the supernatural beings might get annoyed at us humans for talking about them too much. But bodily function swearing depends entirely on what language you use for it! Consider crap, feces, shit, and poop. They all mean exactly the same thing but some sound more objectionable than others. It all comes from the unspoken assumption that certain languages are more civilized and others are more barbaric. If you’re going to talk about bodily functions and you use words which are of Latin origin, you’re probably safe. But when we start using Greek words… god help us all.
So, my conclusion is that swearing started after people migrated out of Africa and started ridiculing the way other tribes talked.