There have been way too many scandals around supplement purity for me to buy into his narrative. Like if someone told me a given brand of fish oil supplements contained 10% of the stated dose, was rancid and full of heavy metals I wouldn't be the least surprised.
But if a fish oil medicine had those issues, I would be shocked, because the consequences for the guilty party would be much bigger, a huge circus of lawsuits and people losing their licenses. That's how I imagine it anyway.