TBH I think it's got to do with how you were brought up.. If your family and friends were doing it, you would learn it no matter what. Programs you watched on TV, all the better ones had swearing (intelligent programs too), so you would be used to it and subconsciously learn from it and swear. Unless you're brought up in the posh (we are better than everyone else) lifestyle, you WILL swear instinctually as the words have become a norm for us all (movies, certain sitcoms, magazines, social networks), apart from private school rich cocky rich a-holes who would NEVER do what the peasants do.
But intelligence comes when you know not to swear, I.E. a job interview. You can be swearing all your life, as I do thanks to South park, but deciding on when it can be right or wrong, will show what kind of intelligence you have. Swearing does NOT mean you belong on benefit street, or scum of the universe, or be institutionalised in a 'special' school, because admit it, they are really just words used everywhere these days, that honestly you will never escape from. Comparing it to intelligence means you are a posh high o mighty prestige perfect human being who thinks every other is scum below them..
TL:;DR Comparing swearing to intelligence means you are Hitler re-incarnated