Any time Sakurai has implied a character had an NPC role in the game, but people didn't get what it meant, he'd immediately clarify it and clear the confusion. Other times, he even adds a little addendum going like "BTW he/she is an Assist" as if he knew people could've potentially mistaken their NPC role with a playable one and get false hopes (like with Ashley and Takamaru).
So why would he not say a damn thing about Ridley after so long considering the uproar that's going on?
Hey, you were the one that reported someone for posting something that wasn't even a slight bit offensive or directly mocking you.
Just to clarify, that's a translation quirk. The japanese version mentioned a "stage boss gimmick", throwing that out of the window.
It could be the case that Sakurai wasn't referring to Ridley and just being a troll.