But it's important to understand that these feelings are what such attacks are intended to invoke. They're intended to harden the gap between "us" and "them", to make Westerners despise anyone who looks conveniently foreign enough to be suspicious of belonging to "them" and to use them as scapegoats for the perpetrators who have often already escaped justice through death.
These atrocities weren't committed by "Muslims" just like the atrocities in the UK during the Troubles were not committed by "Christians". The perpetrators were individuals -- even if they belonged to a group that group wasn't "Muslims", it most likely wasn't even "ISIS"; just a small group of like-minded dangerous individuals who were convinced they would aid mankind by committing atrocities like these.
In so far as certain ideologies led to these convictions it is important to understand that you can't kill ideas with weapons. Yes, where there are armies fighting for dangerous ideologies they need to be stopped, but where you can't even clearly distinguish the soldiers from the civilians you need to destroy the ideology, not the people.
But unlike people, ideologies are very difficult to destroy and take a long time to fully extinguish. And in times like these it's far too easy to fall prey to politicians promising fast satisfaction rather than a long-term strategy towards a shift in ideologies.
We need to embrace our humanity and liberties. We have already had our period of enlightenment and we have overcome totalitarianism and theocracy. We must not allow ourselves to regress to the dark age, no matter how appealing it may seem in times like these -- neither here in Europe, nor oversees in the US.