I have no idea if there's supposed health issues related to it. I think it's about whether it's comfortable or not. It's comfortable for me to sit legs crossed, but then I'm not a man. Anyway, the point of the picture was more that men don't have to sit legs crossed, nor wide open taking more than one seat. Men are fully capable of sitting normally with legs open, while only taking single seat.
Oh...excessive sitting increases circulation issues and chance of blood clotting, but I doubt how one sits matters all that much to it.