Sectarianism Killing Iraq

The news from Iraq is becoming worse every day. Young men are being killed for being named Omar, or for wearing shorts. Sunnis are pitched against shiites and no one seems to be able to stop the killing. What is the cause of this fitnah?

[6:159] Those who divide themselves into sects do not belong with
you. Their judgment rests with GOD, then He will inform
them of everything they had done.

[30:32] (Do not fall in idol worship,) like those who divide
their religion into sects; each party rejoicing with what they have.

[42:14] Ironically, they broke up into sects only after the
knowledge had come to them, due to jealousy and
resentment among themselves. If it were not for a
predetermined decision from your Lord to respite them for
a definite interim, they would have been judged
immediately. Indeed, the later generations who inherited
the scripture are full of doubts.

Meanwhile, marines in Haditha are killing women and children.

Iraq