Quote Originally Posted by kaynide View Post
No we are talking in FFXIV, but I’m talking a human on earth decided how to organize them before the lore was even written, and that said human decided that BLM two thirds of spells would not be Umbral despite the name clearly meaning dark or “black” magic.
Except that "umbral" observably does not "clearly mean black magic" within the story, so nobody made the decision to give black mages "white magic". Inversely, by deciding to give black mages those elements, they made it a fact that astral and umbral are not the same thing as white and black magic. Whether that was a good idea or not, it's canon now.

Additionally, all six elements can have an astral or umbral charge to them, so the grouping seems somewhat arbitrary in any case.

From what I've read in the past, apparently 1.0 approached it differently anyway, with thaumaturges being focused on astral and umbral magicks and conjurers having power over all six elements, but that got reshaped into our current simplified pathway from class to job.