Many Europeans have the will to fight, but their governments have convinced them to think individualistically, and the current violence will pass. Europeans and Germans (for Example) in particular don't well on the past their ancestors committed. They have in fact been paying for the sins of the past since the end of World War 2, and to this day pay not only for the Re-Unification Tax, but for the EU. They can afford this as their Economy is strong, and figure just as other groups (such as the Turks) integrated, the new arrivals will integrate too. The "refugees" are economic migrants, for the most part. of the Hundreds of Thousands that have arrived over the past few years; what percentage committed such heinous acts as you have referenced; and how many have lived as economic migrants of years past have done, and avoided confrontation, kept their heads down and tried to get employment or some form of economic assistance.
guilt will not be felt on the part of the vast majority of the working class people of Europe; but rather apprehension as to the influx of new laborer, ready to undercut them for jobs. The Polish in England are europeans; and by an large from a similar "culture" as the English. But living a dozen to a house working for half an Englishman's wage is what they do to survive in this world and hence Brexit.
Yes, Many European nations are build on their exploitation of their former colonies, the people the majority of europeans will not say they themselves feel guilty. They do not accommodate new arrivals because they feel it is an evening of the score, but rather they feel they are an enlightened people with enough wealth to go around, and can bring in new people, help them, and they too will become German, Swedes, Brits, and Germans, regardless of their origins.
To be honest, they are not guilty but Naive. the people that are arriving are people that have fought and scarped by to survive, and it will take a couple of generations to get those tendencies out of people.
Take a young man, who has lived through violence and poverty, from a slum in Pakistan or India, and bring him into a posh area of his respective Nation's capital city. allow him to live on the government dole. tell him he is entitled to this and that, regardless of his education. and let him live that way for 5 years. do you think it will imbue in him a sense of gratitude to the people who provided such a life or find them a naive people.