Somewhat. It really kind of depends. It can be that. It can be a visceral thrill at the intellectual understanding of what one is setting in motion. (A fire can be considered an early manifestation of network effect. You invite the coordinated release of energy in proximate fuel sources). It can be a symbolic thing (catharsis through slipping out of the bonds of civilizational control and unleashing the most primal manifestations of the oppressor on themselves). It can be an act of creative destruction, (a time to build, a time to destroy; ashes to ashes). It can just be liberating in the sense the ensuing chaos causes an incontrovertible shift in the world around them in pretty much any sphere you can imagine. It can be joy of equality found at last. All are made equal in the face of Natural forces. For some it's about finding resonance between a state of internal emotional turmoil and external circumstance. (I want to burn until there is nothing left to burn about.) Or think of how one in pain may injure themselves or inflict an acute pain on themselves to distract them from an unceasing pain. I have a feeling that for many, it's as simple as "it felt like the thing to do at the time".

Interestingly enough, arson was one of the original capital offenses in many traditions of justice systems as the building techniques of primitive cultures are often not terribly resilient in the face of malicious fire starting.

A DDG search for "any studies of arsonism" and "specialist in psychology of arson" found many sources.

A quick skim indicates that arsons all share the common property that they are generally AFU'ed:

https://www.urbandictionary.com/define.php?term=AFU

Ran into a kid at a birthday party that had an unhealthy obsession with sneaking the matches away. The look on their face when They realized I was watching, and the other parents were distracted, was disturbing. Their parent blew it off, but the obsession was intense.

well it looks like the perp's accademic area was criminology so maybe we could ask him

Bolshevism. This dossier points to a person that believes they are saving the world.

What in the world does this have to do with Bolshevism?

Bolshevism is the belief that the system must be destroyed by an onslaught of random chaos before the glorious revolution will be possible.

Bolshevism has nothing to do with "an onslaught of random chaos". Maybe you have it confused with a crude understanding of Nihilism.

No, it's not. You've conflated a rigid hierarchical party system with discordianism or accelerationism.