The point seemed pretty clear that the terms "mountain bike" and "gravel bike" have become so encompassing as to be meaningless, and that non-racing, multi-terrain bikes that are neither of those should have their own category in order to more accurately differentiate them for the consumer.

I don't have a strong opinion on the nomenclature, but I agree that the terms "mountain" and "gravel" carry connotations that don't apply to all the bikes that get categorized as such.