Very good points. As I said, I don't mind cursing in entertainment when it is judiciously employed to further the plot, but curses, by their very nature, are high-powered words; so when you use too many at once, the whole point of using them is rendered moot. Sort of the "super" argument from The Incredibles: If everyone is super, then no one is. If every word is a curse, then curses no longer have power, and they become equivalent to a 4 year old running around saying "poop" over and over -- laughable and a bit pathetic.
Curses are sort of the storytelling equivalent of a condiment; properly used, they add color and flavor to a story, but when you overdo it, all you can taste is that one element, and every other aspect of the story is smothered by them. Just like I wouldn't enjoy drinking ketchup directly from the bottle, I'm not impressed with dialogue that is all condiment with no meal underneath.