Whether DeFi's "decentralization" is a false proposition is worthy of further investigation. When it comes to their own interests, investors always hope that Tether, Circle, and Binance will stand up to solve problems in a centralized manner, but does such behavior lose the original intention of DeFi development?
I think we can distinguish further between the system and the user itself. The system, most of the time, works quite "decentrally". It depends on how you define decentralization, whether it uses the smart contract as the backbone or not, how many nodes run/support the network etc. The user, on the other hand, can act whatever they wanted to. But they should realize that they already bear the risk when they use the platform. How they behave doesn't really define how the platform works.