Huh?
Perhaps, they sweat more. They probably erroneously think more sweat equals better work out. This is wrong. You sweat enough to keep your largest organ in your body - your skin - cool. Inducing an artificial sweating of this kind spells disaster.
That said, did you mean they were scratching their balls in public.? I see baseball players "adjust" all the time, spit just when the camera is on close-up. These are disgusting habits. Children learn this, they think it is cool and they imitate. If this is what you meant, I am with you. Yes it downright embarassing.
Raphael Nadal (tennis) scratches his a$$ everytime just before he serves. It is downright disgusting and discourteous. Won't their coaches tell them to stop the damn practice? What's up with that scratching?
Roger Federer... ha... there is a perfect gentleman. He does not scratch, does not spit, not even touch ... hhhhhmmmm.... you know.... there.... down there... you know.... and for that matter he barely sweats even in a tight game. It is a treat to watch him play. He respects the audience. I am sure in his privacy he does all kinds of things, but who cares?
On live TV, you better behave.