I 100% agree that confirming cancellation will only kill a book faster. Truth is, I think even posting these rumors is detrimental to a book that's on the fence. Not saying people are wrong to do it, but threads and posts like this nonetheless have that effect. And writers/editors know it.
But again, Ewing in theory can simply choose NOT to address the issue publically. Not commenting on what so far is just a rumor isn't the same thing as flat out denying it.