In debates, when the lights are on you and you are being put on the hot seat, you do not want to appear to sweat.
Remember the commercial “Never let them see you sweat”?
This is very real.
I know that it sounds and looks petty, but a fan should have been put on each side just to keep it even.
That’s why they say that if you listened to the Nixon-Kennedy debate on the radio, Nixon clearly won. But if you watched it on TV, Kennedy clearly won, because of Nixon’s flop sweat.