The main concern with Libra is not its centralized aspect, after all it will not be the first centralized coin out there, but privacy. How can Libra users be sure that their data and movements will not be tracked, stored and sold or leaked? After that widely known data leak scandal, how can anyone trust Facebook at this point? Are people really going to ignore this?
Indeed, this is quite an issue. And Facebook is very much aware of this. In fact, they have actually responded to this already. David Marcus of Facebook has this to say:
"You wont have to trust Facebook to get the benefit of Libra."
"We will not have any special rights or privileges. Facebook created a subsidiary Calibra that will operate a wallet service on top of the Libra network, and while Facebook Inc owns and controls Calibra, it wont see financial data from Calibra."
"Facebook will not control the network, the currency, or the reserve backing it."
"Facebook will only be one among over 100 members of the Libra Association by launch."Sources:
https://metro.co.uk/2019/07/05/facebook-dont-trust-us-use-libra-cryptocurrency-10116398/https://www.coindesk.com/facebooks-david-marcus-libra-crypto-users-wont-have-to-trust-us
And as what I have learned and understood, Facebook, as a single member of the Libra Association, will only have a single vote as well. They will have the same equal footing as the rest of the founding members of Libra.
I interpret all these statements as a step to insulate Libra from Facebook, whose data issues and reputation have really made them look untrustworthy.