School shooters, which was our IRL topic, are overwhelmingly white and male. Mass shootings tied to terrorism are another topic, but the motivation for those is clear.
What isn't clear is why young, mostly white, males (without any political motivation) kill their peers in mass shootings. I've seen the video game narrative being pushed recently, but as the rest of the world plays the same games without the resulting mass shootings (Japan, UK, So.Korea) it's not the likely answer. The same for violent movies. We are an outlier here, and we need to understand why.