IIRC Stem cell reserarch is limited in the USA given the puritanism in its society and laws.
I wouldn't say that Stem Cell therapy is a scam per se.
Sometimes, laws fall behind progress in some countries.
Here in mu country there are A LOT of stem cell related scams. But that doesn't mean there's not some real R&D going on .
Why is crypto avoiding US laws?
Edit: Also, a quick Google of top stem cell research companies show that they are based in the U.S. or Europe, so I’m not sure how correct the claim of US avoidance is. But even if they are avoiding the U.S., they are choosing Europe instead, where “legal flexibility” is still not a thing.