Saying nothing would have been fine. But when they "open the door" to questions (to paraphrase a term from the principles of evidence law) and then refuse to answer a question, they build up hype about something that may mean nothing. Maria's "I should just RAFO this but..." shows the mindset behind it. It's all about projecting an aura of mysteriousness even when it's unneeded.

As for the community, the thing that has kept it speculating has been the inordinate amount of time the series has been going on. People want resolution, and when they're denied that they start inventing their own in the interim. Answering questions that aren't vitally important to the last two books isn't going to harm the community.

No, the only thing that will do that is publishing the last two books and finishing the series. However, there are enough other books out there to talk about at that point.