I second Ices' notion that it is just part of a lot of people, particularly when you have someone that just got shot up, sometimes in very uncomfortable areas and/or unjustly so. Do people need to keep it under control? Absolutely. Hey, I'll admit my own language at times isn't exactly up to par for dinner at the Vatican--everyone in my family has an intense personality. I'm Irish/Scot/German/Choctaw--if that's not a recipe for volitility (with some families, thankfully not mine, alcoholism), nothing is.
Swearing is a powerfully entrenched and unpleasant habit. Often it doesn't even occur to people. You only realize it in the abscence of it, like if you have a family of your own or in company that noticeably doesn't swear. It's just practice. I could go an entire day without an explitive, or very few, and some days they spring up like weeds, either way without noticing it unless I really make an effort to think about it. Ideally I'd like to be without it, but that's a struggle that often slides out of the priority list.
Want it cleaner? Just speak your own dialogue and usually it catches on. You can't enforce it as a rule, but example does go a long way towards curing it.
