Personally, I don't mind swearing. However, when someone swears constantly, it lowers my opinion of their intelligence considerably. I guess that's mainly because of steryotyping. The smarter people that I know (myself included, honestly ) use little or no swear words. However, I would also say that it's because using a swear word in place of a more "civilized" word pretty much says that your vocabulary isn't large enough to express your feelings without that swear word.
One thing to keep in mind, though, is that people invented languages and words for communication, so, in a sense, they don't even really exist. Yet, people will become very upset over something someone says, and might even kill themselves. It's kind of similar to this: if someone loses in a board game - which is something people made up - they aren't going to kill themselves. It's pretty irrational, in my opinion.
One thing to keep in mind, though, is that people invented languages and words for communication, so, in a sense, they don't even really exist. Yet, people will become very upset over something someone says, and might even kill themselves. It's kind of similar to this: if someone loses in a board game - which is something people made up - they aren't going to kill themselves. It's pretty irrational, in my opinion.