It didn’t have to be revealed. That Quirrel was Voldemort was obvious almost within the first chapter introducing him (eg already taken for granted in the earliest top-level discussion page in 2010), to the extent that fandebate over ‘Quirrelmort’ was mostly “he’s so obviously Voldemort, just like in canon—but surely Yudkowsky would never make it that easy, so could he possibly be someone or something else? An impostor? some sort of diary-like upload? a merger of Quirrel/Voldemort? Harry from the future?” Bragging about being the inspiration for a character so nakedly amoral, at best, that the defense in fan debates is “he’s too evil to be Voldemort!” is not a great look no matter when in the series he was doing that bragging.
It didn’t have to be revealed. That Quirrel was Voldemort was obvious almost within the first chapter introducing him (eg already taken for granted in the earliest top-level discussion page in 2010), to the extent that fandebate over ‘Quirrelmort’ was mostly “he’s so obviously Voldemort, just like in canon—but surely Yudkowsky would never make it that easy, so could he possibly be someone or something else? An impostor? some sort of diary-like upload? a merger of Quirrel/Voldemort? Harry from the future?” Bragging about being the inspiration for a character so nakedly amoral, at best, that the defense in fan debates is “he’s too evil to be Voldemort!” is not a great look no matter when in the series he was doing that bragging.