Why Do The Big Questions Always Come Up At 3:00 AM?

No, Nick - let's talk about that .. (that sounds like a psychologist er sumpthin)

Do you think the music influenced the crimes, or the music was an excuse for the crimes? The kids who have committed murders or suicides and blamed music ... wanted to do it because of 100 other influences that misshaped their minds.. And then they heard a song that reinforced what they already thought.... Charles Manson thought that Rocky Raccoon was about the black race rising up and taking over the world... It wasn't, but he made it fit his agenda. He was already deranged long before the White Album came out.

Yeah, I guess it would be pretty silly to say there was one thing that made someone commit a crime. Seems like it would have to be a combination of factors, one of which could be cultural (movie, video game, musical, etc.), but cultural factors seem unlikely to be enough to make someone commit a crime. I don't think there's any definitive way to answer your question at the beginning of your paragraph.

Do Rage Against The Machine fans really believe all the leftist rhetoric being spouted at them is sincere despite the major label/corporate connections the band has? I don't think their messages are taken seriously.

Fugazi live what they write songs about (I guess; it's hard to say many of their songs are explicitly political). They produce and release their own records, they book their own tours, etc. Thus, many people take them seriously.

If Cannibal Corpse went around murdering children and raping nubile young women, people might take them a bit more seriously. Of course, their fanbase would shrink immensely because people tend to be repulsed by such things.

I think it's the behaviour of the artists more than the lyrics to their songs that influences (or tries to influence) the behavior of their fans. If Band A writes a song about boycotting child labor but performs wearing Nikes, they're not going to be taken seriously (by people able to see the outright hypocrisy.) If Band B espouses veganism and abstinence from drugs and alcohol, and lives that lifestyle, then their music/message is more likely to influence people. (Taking extreme straight edge was the first example that really stood out to me; bands got the shit beaten out of them [and maybe they still do] for "selling out the edge" or whatever, so at least /someone/ takes the message seriously.)

Saying that you shouldn't let music influence how you think is ridiculous; It's the same as any other type of art. I can look at a photograph of mass graves during the holocaust and be upset by it; listening to a song about the same thing and not being upset wouldn't make any sense. If music didn't make us feel, why would any of us listen to it? Even if it's as simple an emotion as "that makes me happy" or "that sucks," it's still a reaction one can't help but have.