It’s an exclamation point on the most exciting play of the sport. You’re not directly taunting an opposing player all you’re doing is highlighting an exciting play you made. Just heard the Toyota Center get the loudest it has been all night while up 20 against the defending champs and a whistle takes the air out of the whole arena.
The safety of it is because it’s easy. There is zero danger to hanging for an athletic person. The techs are not for hanging