There is an Arabic aphorism that runs: “El-Islam nizaam kaamil wa shaamil” – “Islam is a total and complete system of life”.
There is nothing in our lives – nothing we do, nothing we might want to do – for which Islam does not provide practical guidance and ruling. Where other religions announce pious (but unrealizable) moral injunctions, Islam offers practical legislation. Where other religions simply (but ineffectually) condemn, Islam enforces realistic and effective regulation.
Men have sexual urges. There is no sense in denying this. These urges are natural (ie. a gift from Allah). Islam acknowledges the existence of these urges and provides the legislation necessary to manage them in such a way that the best interest of the Islamic community is served.
With respect to Cologne one can ask:
Which women, according to Islamic law, is it halal (licit / legitimate) for Muslim men to use for non-consensual sex?
Under what conditions, according to Islamic law, is it halal for Muslim men to rape those women?
Were those conditions met in the square outside Cologne Station on NYE?