Branduil
Hero
Well, in earlier surveys their support was still high enough to keep them, so I think something did change there. It's quite obvious some people didn't like them, it's not like the Aardling opponents were shy to express their opposition. So yes, my supposition is that what changed is that as a response to the OGL disaster, the design team is going conservative to preserve the most widespread support."People didn't like the thing I liked which makes WOTC bad" is a poor argument. Branduil, people didn't like it, after multiple attempts at it. Why would they support stuff people don't like at the expense of pages devoted to what people like?
As for why they should support stuff people don't like, well, designing a game to always please the least-common denominator and never taking any interesting design risks is how you end up with a game as generic and bare-bones as 5e in the first place. Obviously I'm not going to argue it's an unsuccessful tactic, but it's just not interesting to me any more, and signals to me they don't want to take any risks at all in their design.