Pretty much exactly that, in fact what he claimed to be childporn was in part just gay pornography... a common libel made against gay men. If there were child porn on fullchan then the anti-gamergate person who downloaded and public distributed it would have been arrested for distributing child pornography. He was cleared by the police, therefore there was no child pornography.
This was right up there with the GNAA paying people $20 to tweet misogynist slurs and threats... and Zoe Quinn retweeting their offers to astroturf.