Mass shootings in general aren't just a problem with "gun culture", they're an indicator of much deeper cultural problems. Contributing factors include: self-centeredness/selfishness (see libertarians, teaparty, and now GOP), promotion of violence (see Hollywood and FPS games), and yahooism in general (see teaparty). That doesn't mean that a specific mass shooting is political motivated, just that the mindset of some political groups degrades society and that makes mass shootings more likely.