I think he's a very bright guy, but he's also a guy I'd bet has no idea how much he doesn't know or understand.
I don't get that impression. I get the impression that he is a very opinionated guy and that outside his area of expertise (fight commentary/presenting) he basically defends whatever position 'feels' right to him based on the bare minimum of 'research'. On most topic he discusses he throws out all of the usual gambits- 'I'm just asking questions.... are you saying there are no government conspiracies... corporations control everything...' and doesn't seem to update this line of thinking when it is countered. There is a reason that he is super popular with stoners and college bros; he's basically a grown man making the exact same kind of arguments you hear people spout in the wee hours after some college party.
Cryotherapy isn't necessarily quackery it's just hard to get good clinical data from a test because you can't really do a blind test plus there are some plausible physiological mechanisms.
You could pretty easily do a blind test- you could, for instance, just make the temperature low rather than extremely low. It wouldn't be hard to get good quality clinical data but there isn't much interest in doing so because cryotherapy is doing well enough regardless of the existence of compelling clinical evidence. I sincerely doubt that Rogan's interest in the therapy was based on his thorough review of the relevant research literature, it seems much more like he reads (some of) the sources that advocates provide and think that critics must be unaware/ deliberately ignoring such studies. But in reality, critics are putting such studies in context and also considering their quality.
As for Alpha Brain ( I don't use it ) they aren't doing anything malicious they truly believe in their product and they'll give you a full refund if you don't like it. Plus they've done at least 2 randomized controlled studies on it.
This is a really flimsy defence. Lots of homeopaths, faith healers and psychics believe in their product too. Does that mean they shouldn't be criticised? The full refund thing is also a complete irrelevancy. Companies that offer money back guarantees know that only a tiny proportion of customers will ever take that option and yet it gives them a marketing tool that they can use on everyone. As per the randomized controlled studies, again this is a marketing ploy that falls apart if you spend any actual time to investigate the claims.
Did you look at the 'controlled studies' they post on the website? They are terrible.
Study 1 is a 'Proof of Concept' poster presented at a conference that involves a sample of 17 people comparing 16 outcome measures (of which only 2 reach significance, incidentally the same number that are different at the start of the study!). That's a joke.
Study 2 is an actual paper with a sample size of 63 (30 per group), better but still very small and again we have an insane amount of outcome measures now increased to 26! Yet once again only 2 outcomes reach 'statistical significance' (different ones this time). So again this paper is a joke. It is not a proper study. By sheer chance running 26 comparisons at two time periods you would expect 2-3 outcomes to reach p<.05.
AlphaBrain aren't interested in the actual studies though, just in the credibility it lends them, such as you citing that they have done 'at least' 2 "randomized controlled" studies to support their claims.