I think a lot of young people swear because they hear it on TV/the net or whatever and pick it up as acceptable language without meaning. More and more nowadays I meet teens who swear without realising it, because they barely register its potential to be offensive. It's a shame because when they actually do want to offend, the level of obscenity has to step up a stage further and they go into overkill!
What really gets my goat though, is that they don't know *what* they are talking about. For instance I have heards teens call eack other "prick" or "douche" (which definately comes from US tv, in the UK I never heard it used outside of the medical profession until very recently) but when they are asked what the words actually mean, they don't know. So I ask them why they are using words they don't understand, do you really want to call someone something if you don't know what it is? Incidentally, when I asked one 14 year old to ask his mother what a douche was if he wasn't sure, he declined ;)
Thatâ€™s actually pretty true, a few swear words Iâ€™ve heard I never really knew the meaning of. Like cunt and twat were vagina and I did know until I recently looked it up that bugger meant butt-sex.
Generally I try not to swear partly because it seems lazy, I donâ€™t want to offend anyone and I donâ€™t like using the same words over and over again - I think that might come from listening to Just a Minute. However just hearing it used so often they slip out.