i am muslim .. Islam is a great religion .. and this is a bad & wrong act..no one can understand it.. really muslims can not do like this acts .. Because it is a religion of peace[link] just a few people do that .... this is the truth.. 'I apologize because my English is a little weak'.
also on the comments, 1) i guess as long as someone does something that doesnt hurt others, on his own will, its pretty much their business... 2) they arent mourning just the martyrdom of ali, but the deaths in the battle of kerbala(includes imam hussein) 3) just like heavy metal, this is probably the last bastion of real men getting together and beating their chests... xD
im muslim too and sunit (dont know if that is spelled same in english) and very religous indeed
I can definately say that sunits do not make any crazy f**ing stuff like that! they transmitted an article on german tv some months ago and as long as i can remember these meetings are very common in Iran (not absolutely sure)!