… for most people, centralized and decentralized services are functionally identical: in neither case people know the people running their instance personally. in a decentralized system you can pick between that one person you don't know or that other person you don't know. And your data is then shared with more instances whose operators you don't know.
In a centralized system, it is at least clear who's running the entire thing, there is a structure that can be made transparent.