I'm not sure it's been established this incident was anything more than a bunch of drunken young men lusting after nearby attractive girls on New Years eve.
On the contrary, there is zero evidence to suggest it was mere high jinx. It was pre-planned and highly organised, with many individuals reporting some form of sexual assault, ranging from groping to rape. Some women were groped so frequently and roughly that they have bruises all over their bodies. Other reports claim that women were surrounded by gangs and assaulted, having to fight their way free with the assistance of their friends or partners.
Disgusting. Still, that makes me just as bad for telling my teenage daughter not to walk home alone through back-streets. If something happened it would clearly be her fault, at least that's what it amounts to - right?
I agree that the mayor's comments sound pretty bad, but arguably she is correct in principle, just as you are correct to advise your daughter to take a less risky route home. But where I think the mayor has got it wrong is in making it sound like such behaviour is to be expected or accommodated somehow - although I didn't read what she said in full.
It cannot be stressed enough, however, that the blame lies solely with the perpetrators of the violence, and that this type of incident is incredibly serious and demands a wide-ranging response. Far from dismissing it as just a bunch of drunk guys behaving badly, this incident is so far out of the accepted norms of German (and European) society as to cause shock and consternation across the continent. The mayor's comments might be misguided or poorly worded - but the behaviour of these men is what is truly disgusting, and we shouldn't be deflected from that fact.
Way back around the time of my 20th birthday, my girlfriend and her sister narrowly avoided what might have been a horrible incident when they were touring India. They noticed a large group of men were following them along a beach, and several men had approached them or cat-called at them shortly before. Luckily for them, they met a couple of fellow backpackers (complete strangers, but friendly) and they quickly got out of there. Is it wrong to tell young women who go backpacking in India to be alert when visiting certain places, because they are at considerably higher risk of attack in these places than they are normally used to? I don't think it is, even though it is pretty horrible to say so.
This is one of the key issues here - German women are facing a situation where their own home towns - places they are used to - becoming places where they are now at higher risk of assault because of the presence of huge numbers of men who are used to treating women very differently to the way German women are used to being treated. In the face of such increased risk (if that is really the case, of course), it is arguably wise to exercise a bit more caution - but I can't stress enough that it ought not to be the case. Sadly, we're not talking about what ought to be, but what is the case. Just as your daughter ought never to face being attacked in the street, it is a possibility and you are wise to at least address the issue of how best to avoid risk as much as possible while maintaining one's freedom to do what you want to do.
