So...why are level 50 players doing level 5 fates?

[Elladie]

Well, they're not high level if they're doing low level FATES because they get level synced and their gear scales down accordingly. If they are level 50s, they aren't doing them for EXP but for atmas, alexandrites, or lights. Atmas have to be farmed in specific zones, and some zones - like Middle La Noscea - only have low level FATES. If they're not level 50... well ... who knows why they aren't choosing a zone more level appropriate. But their level is still synced down to something much closer to yours