All these rituals are really to demonstrate to others how devout they are. The really devout don't seek an audience for their self-chastisement. Sandy's shirt is probably just visible, but what of those who place stones in their socks to suffer quietly when walking miles on a pilgrimage, and then there are those barbed wire underpants - what are they called?
Chest beating in groups. It's a step up from apes I suppose but surely humans are evolved enough not to be doing this. I like the way the pretty boys sing though.
These are Shia Muslims and what they are doing is one of the reason why majority aka Sunni Muslims have differences with them. It is against Islamic teachings.