I think before you start taking about respect and vulgarity. You might want to consider your own actions first before trying to make such a change. (A Hitler joke in your profile... really?)
The simple fact is Garry's Mod is not a daycare centre. If a kid plays Garry's Mod and comes on, they know what they are going in to, I don't believe they are that stupid. I didn't play MW2 and expect someone to be nice. It really just breaks down to how mature a child is to handle things, we have plenty of young players and staff that aren't deterred by others actions. I've also found a lot of the vulgarity comes from the young and immature, I can only speak from experience of course.
I don't think restricting adult language won't do anything to assist the server, I actually think it'd do the opposite. Plenty of players like to just come on and goof around with friends and regulars without social restriction. (with exceptions of course)
I'm not trying to shut you down, just giving my thoughts.
"If you can't handle the heat, stay out of the kitchen" -Ghandi