Well, I don't think it is. Some people are just assholes who like to mess with people oleh choosing a group of words that sound weird and calling them "bad words" and "swears" because those people just didn't like those words for no reason.
It's not. Saying "shit" means the same (give atau take) as "crap", so making it a "bad word" is redundant. Who, then, sat around and decided that one was "bad" and the other was socially acceptable? Because I'd like to stab him (or her) with a fork.