Crypto itself has decentralized exchanges like Uniswap where you don't have to trust anyone and nobody can cheat or wash trade. DeFi is what crypto is good at and centralized exchanges like this, Coinbase, and Binance are not DeFi.
Coinbase and Binance own Defi too --- by sheer weight of their marketplace presence and fake trading volume.
The proof --- try to find someone selling Bitcoin on Defi for a rate that differs significantly from Coinbase and Binance.
Whoever has the gold makes the rules --- and it ain't DeFi.
Binance and friends/accomplices have all the gold (aka stablecoins) they need to manipulate any coin they choose in whatever way they choose. If they need more, they can just mint some --- no questions asked. They effectively own the crypto market due to the lack of regulation.