...because they rock (especially if you have sensitive skin). I just about wept from joy when I started using 1. Back when I used womens' ones of various brands, I just about wanted to throw them at the wall. They were both utterly flipping useless and terribly irritating for sensitive skin.
Good mens' ones are cheaper, more effective, don't cause any rash, have a half a million different attachments, convinient holding racks AND are not coloured in hideous pink. Yet another installment in the 'mens' products are better' category. Had I discovered mens' electric shavers earlier, it would've saved me years of grief due to struggling with nasty hair removal methods.
The consumer patriarchy is alive and well...