Credentials aren’t everything but at the least I want someone to be in the field doing things in practice (research or patients) everyone else including me should shut up otherwise.
I don't see evidence that this person knows what they are talking about. I see they talk a lot about it, but we know very well that talking, including in the specific manner they do (at length, citing lots of stuff), are also traits of people who are completely deceived or deceiving, conspiracy theorists and fabulists, etc.