What do you mean in US culture? Avoiding vulgar language isn't a phenomenon unique to US. If I was in France I wouldn't exactly be saying <putain de merde> around my family, if I was in India I wouldn't be saying <bhain chod, nai kaam karta>, etc.

US culture varies widely. My parents are fairly conservative so I probably wouldn't send it to them, but I'd happily send it to any of my friends and maybe even my coworkers

In most of the world, swear words are considered unprofessional or rude.

If the words weren’t taboo or offensive then they wouldn’t be swear words.

There reason he doesn’t say “Stuck at Darn home” isn’t because of the aesthetics of the sounds or because of any real difference in definition except to the extent that Darn doesn’t carry the social “baggage”, which is purely a function of it being taboo or offensive.

The use of curse words almost completely derives their value from that fact, even when uttered under your breath after hitting your finger with a hammer.

Sounds like a bunch of humbug to me.