The main sub r/pewdiepiesubmissions was not managed or created by him, as far as I know. Pewdiepie had his own mods for the sub. They went private because trolls were posting links to the video and making memes about the situation. The majority of the users were asking the mods to go private until things blow over. u/agentpao was a troll I believe. r/Pewdiepie_Submissions was just a way for him to mess with the pewdiepie community. You mentioned the poll, but he was also posting gross memes about the whole thing.