I’ve never seen any of his videos, but from what I’ve heard he’s most famous for big charitable stuff, including "#TeamSeas" and things where he gives a heap of money to viewers/randoms with medical bills or something like that.

Obviously, the cleanup project from TeamSeas was actually basically a scam, but it’s not clear how much Mr Beast knew that. Or even, frankly, how much the person behind the cleanup project knew it couldn’t work; whether he was hopelessly naive or wilfully pretending the criticism didn’t exist. And individual philanthropy is a highly inefficient use of money in terms of aid, that might be popular because it has a much higher benefit to the donor (in terms of social credit and thus in terms of ad revenue on YouTube) than working with efficient charities. So from someone paying attention, criticism of him and his intentions could have come earlier, but it was always easy to brush off for those going into it wanting to trust him, presumably because he’s entertaining and comes across as likeable on camera.