sensored t.v shows

as i sat in my room today watching t.v before work i started to watch its always sunny in phili. i started to notice more and more swears being aloud to air, and these swear were the big ones that i know for a fact weren't aloud to be said and i thought about why the even sensor shows. Like i get your trying to protect young innocent minds from hearing the crazy stuff that these people say on that show but that show pretty much got to say whatever they wanted to say. I mean even south park doesn't allow all that and south park is %85 swearing and the other 15 percent inappropriate nonsense. To me i think shows shouldn't be censored at all because now and days the parents can control whatever their kids see on t.v.