If this were some standalone IP, I'd agree 100%. The problem is, "the world" is Dungeons and Dragons, not just BG 3. There are 10s of thousands of stories that are part of "the world" that may not have any impact at all on BG 3, and every time I see "there's a disconnect", I wholeheartedly agree, there is a disconnect. People are always trying to disconnect BG 3 from the thousands of years of history in the Forgotten Realms. Or, more accurately I guess, they want that history outlined for them, because this is the "assumed knowledge" that the characters have, or that some of them will have. In the case of people that have no knowledge at all about the setting, yes, they should be hitting "outside" resources, because the outline could be a real slog to sit through.
Finding the outside resources would be the real slog when basic information could simply be in the game. Pulled up this example from Pathfinder: Kingmaker where I have my cursor over The Aldori Swordlords to pull up the tiny window. Extremely non intrusive considering it is a concise description and you don't have to see it if you don't want to.