To expound on your final point - about how a certain type of man may look to Mangione as opposed to school shooters:

It's really worth noting that almost all school shootings can trace their origins to the example set by the Columbine shooters, Eric Harris and Dylan Klebold. It may be difficult for people to remember, but in certain circles the reaction to those boys wasn't entirely negative. To a certain type of asocial edgy boy they seemed badass, particularly that security cam photo of them with the submachine guns. Some teenagers copied their style. Some famously even thought they both were hot.

Now take Luigi Mangione. He is attractive, seems intelligent, a valedictorian. He targeted out someone who symbolized an industry that's universally reviled, evaded the police almost flawlessly, took to flirt with a concierge, and he survived to tell the tale. He's near folk hero status. People are writing fan fiction about him. Apolitical everyday people are sympathizing with him. The reaction to Mangione is even more celebrated than how certain edgy niches celebrated Harris and Klebold. And ultimately, unlike Trump's would be assassin, he didn't miss.

If the quarter century of a school shootings that came in Columbine's wake of violence is any example, any model, I don't think we are prepared for what may unfold in the next few years.