If we blame guns for murder, we might as well blame spoons for obese people. There were such evil people long before guns existed. How did they kill? Knives and arrows and they killed nonetheless. Look at Switzerland, everybody has a freaking assault weapon but we don't hear of such issues there. Why? They obviously have a better education system in which they are taught proper respect for such forces.
Do we say cars people? Do you hear of "cars killed thousands last year"? No, because that's ridiculous. We hear of drunk or wreckless drivers. An idiot with a car could run over a group of people just as easily as someone could shoot a group of people. A car can't kill anyone without a driver any more than a gun cannot kill someone without a person to pull the trigger. It's 100% up to human decision. Of course, people are going to find any way possible to shift blame and not take responsibility.
When you teach a person that what he feels in his heart is right for him, and he feels killing people is what is right for him, he will carry out his actions to the best of his abilities believing he is fully just and righteous in his actions. This is a result of our crappy education system, not of guns.