I don't see how it's related to inequality. I don't think any of these shooters were poor or went through poverty. For this incident the press showed pictures of a big single family home in suburban Dallas.
The US middle class is shrinking. And it's always dangerous to have lots of young men with no prospects. With no future worth living into.
But seriously, mass shootings are just a sideshow. It's the political implications that are truly frightening.
Are there a lot of parents that won't allow their kin to live with them when the only other option is homelessness?
However they're at a much greater risk of becoming homeless.