The basis is self evident: he is an affiliate marketer for an overpriced product with astronomical margins (investors piled in at north of a billion) making health claims without scientific basis, 3rd party testing, or transparent labeling.

Good on him for getting his bag, but the incentives are clear: he made his name before sponsorships with quality content, but now the demand for ad impressions has outpaced his supply of meaningful insights. He needs to keep churning out videos to earn sponsorship dollars, so it's a natural symbiotic choice to invite low quality guests.

They bring the content (and controversy / engagement / followers), he supplies the veneer of legitimacy, studio lighting and somber expression in the thumbnail. The advertisers benefit and all get their payday, as long as his adherents keep overpaying for processed powder with multivitamin.