The rugers are tanks. But even tanks have been damaged and broken by bad driving.
While its an old story, and may not apply (or apply as much) to modern made guns, flipping the cylinder open and shut is felt to be a bad thing by most of us.
Personally, I've always wondered if the flipping open (especially if vigorously done) isn't the more risky practice. People talk about damage to the cylinder stop from slamming the gun shut, but slamming the gun open leaves the whole weight of the cylinder hanging from the crane, being moved at some speed, and subject to a violent sudden stop.
The weight and inertia of the cylinder exerts force on the crane, at 90degrees from the normal operating direction of the crane.
Sure, its steel, but even steel has limits, and when you get beyond them, it bends. Can it happen? I think so. Will it happen? Not likely. Will it happen to you and your gun? I doubt it.