There is a competitive sdvantage to be gained by feigning injury or exaggerating a tackle. It's the same logic as claiming a corner or throw in when you know you shouldn't be awarded one. This exact same potential competitive advantage doesn't exist in other sports, but where one does people will attempt to manipulate it for their/their team's benefit. Like a player claiming they made a catch in the NFL when they know they weren't in bounds or when the ball grazed the turf first. Or when a QB makes sure the refs notice any late contact in the hopes of a roughing the passer call.