AMD is terrible at helping advertise this stuff.
Call me cynical (or paranoid), I also think display companies are trying to avoid upsetting nVidia as they are currently the GPU market leader by a significant margin.
My UWQHD monitor for example runs Adaptive-Sync 48-100Hz. So whilst it has the gaming abilities comparable to a high end Gsync monitor, nowhere in the advertising material is FreeSync listed (and I'm pretty sure it's been validated by AMD [even if not my point still stands]). Also there's no mention of the 100Hz refresh rate on the extensive marketing front page, which would be a pretty huge selling point in normal situations. There is only a numbered dot point, in small font, literally at the very bottom of the specifications section saying "3)Adaptive Sync support range from 48Hz-100Hz"; The first and last time it mentions either 100Hz or Adaptive Sync.
I'm happy to wear a tinfoil hat whether right or wrong, but I honestly can't see another reason why a company would downplay such features; especially when these features are most important to gaming buyers (the same market nV is after).