I don't doubt that. But that still does not mean that being a Muslim has anything to do with it. In fact, even if it turns out that all of the attackers were Muslims then that still holds true. How that works I'll leave as an exercise for you to work out but let's just say that the basis of a solution to this whole problem is somewhere in there and that I strongly believe that it starts with a complete lack of generalizations and a focus on people as individuals rather than as groups with shared traits. As long as that step isn't taken we will - very unfortunately - probably see more of this.
I see your point. Not that long ago a white supremacist shot up a black church in the name of America and Christianity but we aren't condemning everyone in those groups. However it would be fair to condemn the small society (ghetto if you will) that allowed this to happen. In the same way I can blame the anti-integration Muslims without blaming Islam itself.
I don't feel sorry for individuals that take up arms against me. Every individual is responsible for his or her actions.
This goes far beyond "shared traits". They organize against us with a dogmatic reverence for violence known as radical Islam, and your dogmatic tolerance for it allows it to metastasize.