Either that's true for every setting or it's not true for the Forgotten Realms.
The lore remained the same regardless of what individuals groups did and only changed when the company that owned the setting or Ed Greenwood decided it did.
Drizzt remains a hero in canon even if a DM decides he's a serial killer in their individual campaign.
I agree - it’s true for every setting. Heck, there are many fans who rejected / still reject Greyhawk’s official canon because they felt it clashed with Gygax’s vision of the setting despite TSR advancing the timeline. Also, if the lore is spread out across what WotC says it is and Greenwood says it is, how do they (fans) reconcile them when they conflict if there are two separate lores? Ultimately, they have to choose which one they want to follow but they are then ignoring the other.