If we talk about atrocities in general, they always happen and people get constantly murdered tortured and raped.

But if we talk bout specific mass events like orgies those are extremely hard to organize and coordinate
it is not that simple to bring rapists from all of he world divide responsibilities for everyone and maintain some kind of order and security.

I think it is very likely that something pretty horrible will happen in Europe because of all that migrant crisis. almost definitely there will be ethical cleansing


Considering people becoming monsters those who have high morality are most susceptible, because it is not that hard to prove that murder and torture is a virtue which you should do even if you don't want.

However if we think about human nature itself I don't think that people are that evil in general to do something wrong for someone who did nothing wrong. Those who do that are usually severely damaged themselves and just taking revenge.