So is applying saliva and sweat to the ball wrong then?
You seem to be getting the idea that people are actually putting mint juice on the ball - they're not. They're
improving the quality of their saliva so as to get a
better shine on the ball.
The mints don't do anything to the ball - the mints do something to the saliva, the saliva (and trousers) shine the ball and the ball when shined behaves better (yes, better - the game is about bowling, not batting
) than it does if it's not shined at all.