The object of the game / contest is to win. He did nothing illegal. Whenever I played co-ed anything - volleyball, mixed doubles or softball, I would always hit the ball at or toward the women. frick 'em. If they want to play with men, then they have to figure out how to deal with it.
My ex-wife was a decent tennis player. When we would go and hit for practice, I would just try to keep the ball in play. But sometimes she would say "Let's keep score." After that, I would use every trick in my bag, and she would get pissed off. Probably one of the reasons we are no longer married.