I wasn't trying to take blame off of him, rather this was much worse than it could have been due to poor engineering. If they are to rebuild themselves (literally) they should probably keep this in mind if it were to ever happen again. A fire escape could have easily saved those 20 people from that arsonist.
This is one of those things where multiple people are to blame at the end of the day. I mean if the arsonist didn't set the building on fire, I'm sure something else like an electrical fire would have at one point and this same problem would have occurred
If a building with fire escape routes could save 20 out of the 33 people who were killed in the fire, that's pretty hard to say that it was only the arsonist's fault
It gets worse too, I found an image of the inside of the building posted by a redditor:
No fire doors. No fire walls. Wooden floors and walls. No sprinkler system. A wooden spiral fireplace that ran throughout the building in the center of it. A stairwell that wasn't pressurized, allowing smoke to go in immediately. And I'm hearing on discord the windows were designed not to open to prevent suicide attempts.
That spiral staircase? Per the NHK, It acted as a bonfire / chimney. The worst fire was in the stairwell, followed by the spiral staircase.
This building was pretty much designed to be burned down. It may as well have had a lighting rod sticking high up with a sign saying "I'm feeling lucky" on it.