Maybe the men's squad volunteered to take a cut, and when asked they all agreed. I don't know.
I don't know either if the men donate their fee to charity or not? I know the England players do, but that charity is the FA Foundation, so the money all stays in the game anyway. The England players i believe get £1500 per international btw, plus £500 for a draw or £1k for a win, so it's about £1/2m a year in total to the charity which helps develop the game.
Increasing the women's pay will also help develop the game won't it?