I would think gun owners, of all people, would understand the concept of a few people ruining it for everyone.
OK, so there are 1.7 billion Muslims in the world. How many of them have every killed anyone, in a terrorist incident or otherwise? About as many Christians that have killed someone perhaps?
Just because Christians kill in large numbers with airplanes and tanks instead of whatever they can scrounge up at the local army surplus store does not make it any better.
The US might use the claim that "it's at war" to defend those actions, but the other side will make the same claim. That's the problem with anyone who says "you're either with us or against us", because both sides are claiming the same thing! Now, the fact that we at least try to focus those efforts on the people we are at war against it at least a start. The stuff going on in Iraq (with what Muslims are doing to each other) right now is closer to something out of The Godfather than anything war related. Think of the US Marines as the police, and it's not a stretch.
If someone else invaded the US, how do you think you would respond? It would have nothing to do with their religion or yours, it would have to do with you wanting these people out of your country. If someone was over here trying to install Sharia as a way of life, we'd be ticked too. Just because the US says they are making it a "better" place does not mean the people living there are any better off.
I tell you what, as soon as you're done collecting every gun from every gun owner in the US because they are all criminal lunatics, then you can start working on people in other cultures.