I don'ty know what smaller YouTubers have the game, but most likely the dev doesn't give them codes because they most likely don't know who the really small YouTubers are. They just hack the game files to give themselves early access most of the time.
devs should've just told them to post the early access content one day before the game release. Releasing it early when the game doesn't have a release date yet really make people lose interest in the game. Like you got youtubers posting "ALL BONNIE'S BAKERY DLC SECRETS!" on their title. Why would anyone play it when all the dlc secret is already out a few days, weeks before the game release?.