White gravy, often flavored with chicken stock and herbs, sometimes pepper, is particularly popular in the south, and it slaps. Its the same kind of gravy you might have with biscuits and gravy (these 'biscuits' being closer to scones than hard shortbread or tea biscuits) To use a brown gravy in the same scenario would be a travesty, thats mainly reserved for roasted red meats.
This is "gravy" in the same way American squirt cheese is "cheese" in that certain people will call it that. But its categorically a completely different thing.
It's a roux with some fucking liquid added, which is exactly what you do to make any gravy, regardless of the language root of bechamel. Stop being so goddamn pedantic.