If someone wrist flicked my S&W 25-5 4", for which I looked for over a decade, and for which I paid close to $1,000, I'd probably take the gun back and very likely would punch him. HARD. In the face.
I don't advise anyone to do something that can damage a gun. But I once decided to test out the "wrist flick ruins revolvers" story. I got an M&P (pre-Model 10) and played Bogart, first with an empty cylinder, then with a cylinder full of dummy rounds. I flipped for the better part of a morning, hundreds of "flips" each way. I suffered a very sore wrist and forearm. As far as I could tell from gauges and a range rod (alignment gauge), the gun suffered no damage at all.
You treat me and my property with care and respect, and I'll treat you and your property with care and respect.