Keyword ''COMEDIAN''. Whatever makes you laugh be it salty or sweet language, you have options from Anthony Jeselnik to Jeff FoxWorthless (Foxworthy) (that's my personal scale) now swearing doesn't necessarily make a comedian funny, swearing just helps the delivery of a joke or to put it in a clearer context. There are good and clever jokes out there with no swearing.
Most comedians are for adults, part of being an adult is cursing ( but not too much. ) If it's for a 3 year old. Then obviously not. In a club where theres a comedian. Do you see any kids? No. It's just adults so its fine. Also the no side said parents could bring kids, but the atmosphere itself is not really what a kid prefers also even if there was good language kids wouldn't get the jokes.
When you're older you don't repeat it cause you know not to say them. Also it makes people laugh more. Comedians make money by making people laugh to feed his family, have a house, and many more reasons. Now a days people think swearing is very funny. Every comedians are funny that way.
Bad language is considered to be bad for a reason. I think that everyone needs a bit of laughter in their lives, and comediens would have a heck of a larger audience if parents weren't scared to bring their children along in case they drop the f bomb, use racial slurs, use the r word, or talk about inappropriate things.