He is a zealot in a cult of extremists. Did you expect a higher standard? There is only one truth, and that is the truth of his cult, which is so true that to question or disagree with any facet makes you not just wrong, but a bad person, and deserving of punishments that they would condemn others for doing.
Anyway, I am with Wildtree on this- you can't use the actions of a few to punish the many. That isn't justice. That plays into ISIS's hands- they don't want coexistence, and one of the ways they will achieve this is by turning Westerners against all Muslims. We need to be bigger than this. Heck, it pisses me off when the regressive left (because it is ok to generalise, so long as it is your enemy) tars all white men, and all gamers as being sexist racist (who then moan that it isn't fair to generalise all Muslims without a hint of irony or awareness to their own hypocrisy), and I need to defend myself because of the actions of someone who simply looks a bit like me. It isn't ok when they do it, and it isn't (to the people lumping all refugees together) ok when you do it.
Sure, have worries about the impact of mass migration on areas might have (in several places they get sent to poorer areas that already feel alienated, making things worse, you don't see refugees being put up in gated communities), push the government for action on ensuring integration (this isn't racist, it is important) etc, not fully embracing this unquestioningly isn't racism. However blaming all refugees when a small handful do something messed up, that just isn't right, it isn't just.
And if you have concerns about the cultures that some of these people are coming from (which I think can be valid), tarring all of them with the same brush isn't going to make it easy to talk about these concerns, as you give ammunition to regressives and Islamists who can then cite your bile as evidence of Islamophobia/racism, and therefore any questions and concerns about the cultures people are coming from can be dismissed out of hand and anyone who has any questions can be labelled as a racist and silenced. No one wins with this mentality, except the likes of ISIS and the far right. When these are the biggest winners from this kind of behaviour, you need to ask yourself if this is a good thing.