Girls why do you enjoy doing this to guys?

On a night out I saw a guy who offered to let some women step on his crotch god knows why he wanted them to do this. To my surprise these women did it and the 6 of them were doing this for well over 30 minuets they were even laughing and giggling the whole time they really enjoyed doing this to the guy. They stomped on his groin so much that their heels made him bleed from the groin and thats when they finally stopped but why do women enjoy hurting guys down there and if you had been there would you have joined in ?