You're mentioning the Job crystals that most people are okay with people RPing, though. When people aqre wary about people RPing as jobs they generally mean the ones like WHM, BLM, etc. The ones explicitly called forbidden or incredibly rare in the lore.
Ones like WAR/BRD/MNK, where there are people and organizations actively training new people are fine and I never see them being pestered about it.
Yes but they make a very clear point that it's all of the old disciplines - all of the jobs - that are getting a revival, even the forbidden ones.There's a noteable point that it is including every single Job (otherwise, it would say a select few instead).
It speaks in an absolute language - inclusive of all Jobs - rather than speaking in a partial language - using words like "some", "most", or "common". Using the game's story, it is the Adventurer that takes part in the story that "starts" a revival of sorts, but it is apparently being passed on.
For instance, in the White Mage section of the lore it says:
"Some five centuries past, the elementals relented, and did at last allow the legacy of the Amdapori magi to wielded by a chosen few. The Padjal, revered eaders of Gridania, have since served as stewards of white magic and oversee its careful instruction."
Note how they have to be chosen by the elementals, but that white magic is being taught to people by the Padjal? It means limited quanity but that it is not left to just the storyline adventurer.