1. Immediacy is one of the ten principles of burning man, and burning the art when finished forces people to appreciate it in the moment while it still exists. It’s worth noting a lot of art is burned, not just the man.
2. Fire is aesthetically pleasing . A huge percentage of the burning man crowd is into fire dancing and fire arts
3. They burn the Man because that’s what they do - similar to abstract art you can just accept how that makes you feel rather than needing to cognitively analyze it.
4. It connects to both eastern and western religion. Impermanence is a pillar of Buddhism and a man publicly dying is a pillar of Christianity
Of course I don’t think drawing a connection to human sacrifice is outlandish as a ritualistic burning of a symbolic man during a large semi-spiritual gathering is easy to connect to human sacrifice. But it’s worth considering a few other ideas.