MY BRAIN HURTS!
No need to think so hard.
The word "organic" has
many, many meanings. To a chemist, "organic" means "contains carbon." This is not what a bonsai enthusiast means when using the word "organic" to discuss soil.
When talking about soil, we say "organic" to mean "not rock" or "not mineral."
Ergo:
pine bark, worm castings, peat == organic
haydite, turface, pumice != organic.
Now stop thinking so hard.
pootsie