It was at that moment MGS fans were confronted with the fact that the game was just anime all along. And instead of accepting it they rejected it. That wasn't their metal gear. "I see you like... Castlevania!"
I was confronted with MGS1 being anime in 1998.
I was confronted with TTS being a Frankenstein's monster with seriously shitty cutscenes/audiovisual presentation in 2004, and rejected that.