Where I live(Europe), Group 3 is not considered to be a synthetic, and the main reason is because it isn't, and will never be.
A mineral oil will always be mineral oil, no matter how much you refine it.
It's really that simple.
You can claim that Group 3 outperforms PAO and Esther type oils, but what difference does it make?
IT IS STILL A MINERAL OIL!!
Calling Group 3 synthetic, is only bull****-bingo from some clever lawyers, that were able to make their companies more profitable.