Whatever you call it, you can point directly at many Americans - especially young men - leading lives with no purpose. No God. Absentee parents. Tolerating urban violence. Rampant, and accepted, drug usage. Government 'safety net' if you don't want to work. Promotion of 'gender fluidity'. Accusations of racism when there have never been more opportunities than there are today for minorities. A lenient court system.
Pick any one. Put them all together and you've got what we've got today.
Sorry... was about to respond in bed with my phone but decided to get off from being horizontal and from my notebook instead, and less horizontally.
The issues you mentioned -- are societal changes that are happening all around the world -- only at different degrees or pace. Whether the western world is getting less religious or addressing gender ambiguity etc.
IMO. Drug use, increase alcohol consumption etc are manifestations of the core issues -- ie. how people deal with their shit. So some drink -- and some will go postal.
That's the only thing that's different from the rest of the world -- mass shootings.
Directly or indirectly related -- The US has more guns/assault weapons per capita than anyone else in the world.
Nobody seems to be even close in terms of the frequency of mass shootings. Weekly instead of a range of never (like here) to once (like as common as plane crashes) and they did something about it.
My point is that the US approaches the changes (or cultural shifts) that you mentioned above or deals with the frustrations/anger very differently -- as compared with the rest of the world.
There's a cultural issue -- how folks deal with it on a micro-level ie individually or politically -- antagonistically both domestic and political as well as internationally. The constant battling and hyper-competition.
It may have worked in the past to get the best out of things from sales to innovations to geo-politics. It's like on a constant war footing at school, at work and in global politics.
But maybe it's trickling down to the individual and now this is how it manifests itself? Or maybe its the price you pay since its different sides of the same coin.
Then you add the easy availability of military-grade weapons to people of all races... as they say,
bob's your uncle.