It's a really idiotic viewpoint, though? It's like you have absolutely no common sense about how society works?
Society as a whole views foul language as a negative thing. Because of this, kids shouldn't be exposed to it anymore than things such as gore or sex.
Kids are extremely impressionable an often repeat what they see. Obviously not all kids do this, or at least as much as others, but most do.
Kids do not always have complete control over what they say, and sometimes things might slip, which will get them into even more trouble, especially in public.
If society as a whole didn't view foul language as such a negative, taboo thing, then this wouldn't be a problem.
But the fact is that it is a negative thing, which is why it's called foul language.
This isn't the only time that you've lacked basic common sense about how society works, from what I recall, which is why I'm a little ticked.
That, and you don't have to put up with my eldest younger brother all the time. (He's an asshole, btw)
I've never been good about explaining my views, but here's an article I found that explains my thought process pretty well.
EDIT: I only read the first couple paragraphs of this one but from what I read it brings up really good points.