If passing teams really had an advantage when it's wet, they'd leave on the sprinklers all week. They were disappointed it wasn't still raining hard when they came out for the game. He's got a point. Teams keep the ball dry. Receivers know where they're going.
Pass rushers slow down.
Still, when it's wet, bet on the mudder. Depends on the crowd. Frankly, Stoops hasn't been thrilled with Owen Field's environment. He's not saying so, of course. He's way too smart for that.