Yes. There would have been less outrage if the perpetrators weren't taken in, fed and housed, and as repayment for generosity some raped and killed. How would you feel if your kindness was repaid by spitting in your face?
Nationalist outrage? I personally talked to people who tried to help migrants and were rewarded, literally with phlegm in the face. Cologne new years sexual assaults wasn't some contrived story to manufacture outrage. In fact it was actively repressed by the media. The area surrounding the Calais jungle, and the migrants there swarming and damaging trucks wasn't imagined. Budapest train station wasn't a dream. Neither were countless stories of migrants behaving badly along the Balkan Route.
As the flow of migrants has slowed down, so have these stories. That's no coincidence.
But, nevermind all that. You know what 1st came to my mind in 2015 when the migrant crisis really gathered steam? Not a fear that Europe would be swarmed. It was the fear that Euros will Euro and the "cure" to the problem would be worse than the problem itself. Yeah, the migrant crisis is bad, but the reaction and pushback could be much worse. Nobody wants rabbid nationalism to rear its ugly head in Europe, and those in power who allowed this issue to get so far out of hand should have known that it could be an unintended consequence. People can get downright ugly when they feel slighted or backed into a corner. No bueno.
The EU has to really crack down on human smugglers and the NGOs who are ferrying illegals into Europe or nationalism will grow.