He literally threw a forearm/elbow at Steven Adams' head for setting a screen, not even a hard one at that. It wasn't Metta World Peace to Harden bad, but it was still pretty bad. Alot of these NBA guys are fake tough guys who only act tough in the game because they know nothing will happen. Nick Young is the paragon of fake tough guys. It's guaranteed he wouldn't act like that towards someone like Adams out on the street, because he'd get his arse kicked if so.
I mean...are you hoping that Nick Young gives forearms to the head of 7 ft aussies in the street?
It's kind of a weird line to draw in the sand. NFL Linebackers don't tackle bystanders in the street, anymore than they attempt to gouge out the eyeballs of random people like they do in the bottom of scrums.
Rugby players shouldn't go cheapshotting people in the street, but as a guy who has played and watched a fair amount of rugby, I've been punched, choked, and kicked in scrums and rucks enough to know it's pretty common.
NHL players throw punches all the time.
It's a weird kind of analogy.