Yep I don't think insisting will help . . .
I just ignore the "profile" and if everybody did the same then they would be pointless.
However, we are all different, joined by a love of things lycra/tight. Letting people on who are not so outgoing initially (I have face pix on my profile)will maybe lead them by example and therefore pictures might appear as they develop their confidence. I was a shy (lonely) boy once . . .