Uh, hard to tl;dr. Basic points are "putting medical records etc on the blockchain is a bad idea", "bad for environment", "NFTs are all pump and dump schemes", some leaks of NFT discords where people bully those critical on NFTs
He is outright NFTs are a scam designed to be a bigger sucker scam where you buy in assuming someone else will be a bigger sucker and buy it for more than you payed