Swinging your cylinder shut like this is a classic Hollywood move, but it should stay in Hollywood. It's not somehing you should actually do.
Revolvers are pretty darn tough and reliable. But they are subject to wear and tear, just like everything else. And swinging the cylinder shut like this can damage the crane or cylinder stop. And if those parts get damaged, it could mess up the alignment or the timing of the cylinder.
A lot of people may call it a boomer myth, but it is a real thing. To be fair, swinging the cylinder shut a few times ain't going to instantly destroy the revolver. You could probably do it a hundred times and be fine, probably. But over time, if you keep doing it, it's going to eventually cause damage to the cylinder. Revolvers certainly can handle being abused, but there's no point in making it wear down faster than normal.
Don't listen to me, listen to Jerry Miculek. He's one of, if not the most experienced revolver shooters in the entire world. And he says you should never swing the cylinder shut. Not only because it can damage the revolver, but also because its slow. It's much faster to simply close the cylinder with your left hand.
Ideally, you should cradle the revolver with your left hand and reload it with your right. If you master this technique, you can reload a revolver in a split second.
So either way you look at it, theres no reason to swing a cylinder shut unless you want to look cool.