I was watching a very strong technical presentation recently. The speaker knew his subject thoroughly, and spoke with confidence and precision. He hardly stuttered at all. The slides were informative and to the point. But then the presentation ended with a one liner with a curse word in it. It made me disappointed.
Curse words in public writing and speaking is a curious thing. Its "shock effects" can make a weak presentation and a weak speaker appear more captivating. But at the same time, I believe it becomes a distraction and detriment for presenters whose skills and material are already convincing and interesting on their own. In effect, the use of such words "normalizes" speakers and presentations towards some median value. It might be a useful in some limited situations, but in general I believe that using this "crutch" puts an upper limit on the effectiveness one can achieve.
"Crutch" is an apt analogy, since a real world crutch helps an injured person move faster but causes healthy people to move slower than their full capabilities. There is a "crutch-user moving speed" that both the injured and the healthy converge to as a result. A completely healthy person would never use a crutch to move around, since that would only slow him down and make things cumbersome and annoying.
Just like how a crutch weighs you down if you are healthy, curse words weigh down the effectiveness of an otherwise convincing talk or article. But unlike real crutches, it's difficult to perceive this detrimental effect as the protagonist. You often have to rely on an observer to set you straight. I've been a victim to this in my own writing in the past, and it wasn't until I saw other profanity-laden posts and their critiques by others that I recognized my own folly.
I have nothing against cursing in the right setting, for instance in private with close friends. It might even have a place in public speaking and writing, in very limited circumstances. But most of the time, if we're anything resembling competent at our craft, we would do well by eschewing curse words.