Because he was the slave of the rhythm!! He felt the music, he was not thinking of anything when he was dancing..and the music, the rhythm made me do this, made him do those incredible sexy moves..
MJ alisema it was an urge, a feeling that he got when he felt the music... He didn't know why he did it, he just did it. The first part of this video explains but I don't know about the rest... The person who made the video is trying to make it seem that MJ grabbed his crotch 24/7...
Well in the interview with Oprah he alisema that it's the muziki that makes him do that. "You know I'm dancing and I go BAM!" He alisema that lol. He was quite embarressed when she asked him cause the mashabiki wanted to know too and Michael laughed and looked down aww.
It's his muziki that makes him do that, the muziki is inside him.And the making of "Bad" muziki video , when MJ danced and when they finished the making of it, they watched the video and they were surpised when they saw MJ grab his croch.And they asked MJ why did he do that and he alisema that it just happened, he just feels the music, it"s inside him.No one can do the way he does it becouse it's inside him.
As told to Oprah Winfrey in his 90-minute interview, on Wednsday, February, 1993 at Neverland Rand. He only grabs himsell when he's dancing making him a slave to the rhythm.