I haven't seen the movie and don't ever intend to. But based upon what I have read about it I would like to offer another point of contention.
Would the Spock who went back in time in COTEOF to prevent McCoy from changing the past, and who insisted that Capt. Christopher had to be returned in TIY to preserve the future; be so willing to write off the destruction of Vulcan and all the inhabitants, when he knew that this was not as history should proceed?
I submit that the answer is he would not. Thus in the history that he comes from, there must be no conflict, and to his knowledge Vulcan was destroyed. If it were otherwise, then Spock, through inaction, would be condoning genocide.
I'm sorry but the Spock of TOS would not do that.