Motivation is definitely one side of the equation, and absence of better options is another.

I doubt any desire for fame was involved in either shooting.

He belongs in the annals of infamy where his name will be recorded and in the course of time, forgotten. Had he been arrested in some countries he would not have made it alive to the police station and if he did it would soon be pass go and straight to the firing squad.

A few weeks ago, the news told of a kid’s parents who were prosecuted for giving him a gun even though they knew he may be dangerous. Their prosecution is probably ongoing. Has anyone heard more about them?

Herostratus? Do a search on etymology of “hero”.

Didn't know a classical name for a mass-shooter motivation existed.
But I wondered if the ICD-11 or DSM-5-TR have new mental disorder codes for mass-shooter mental disorder. Mental health disorders are too broad a spectrum to expect that mental health classification could ever stop the mass-shooter problem. The only resolution for that is to regulate guns. If children can't go to school with guns to protect themselves, then why should elders be allowed to use the the 'well-regulated militia' excuse. Currently what gun lovers have is not well regulated. [onlinelibrary.wiley.com]

And of course in the end they will fail even in their sick intent. Herostratus may be remembered because he was a "first" but who remembers the names of most murderers, even the really famous ones are forgot in a couple of centuries, because they are such a common dish, todays newspaper, tomorrows packaging pulp.

So many better ways to make ones name last forever... Donate money to a museum, get your name on a bench or a plaque. Work hard toward a goal or set a record of some kind, in a fun and positive way.

Seems to me these "men" are being called to commit these atrocities by dark voices on radio or online broadcasts and chat rooms, saying outrageous things to create and stir up hatred in their minds to make them feel as though they would be heroes if they wiped out a group of people of a particular race or faith or age group.

These "men" want to feel important, a part of something, and if they are not part of a positive group, such as a sports team or hobby enthusiasts, they seek out someplace darker to fit in. That's all I can think of.

I guess within the dark groups where they are welcomed, the herostratism would kick in and drive them... They might be famous in that group, but abhorred by the average citizen.