In my opinion, that concern makes sense because Facebook is the largest social media network in the world with 2 billion users. imagine if all users later have libra. then this libra could have an impact on the world economy. and libra will later be controlled by facebook unlike bitcoin which is decentralized. this is probably what made some countries in Europe reject Libra.
Despite controls by governments and central banks worldwide. I think the wave of crypto currency is unstoppable. Though it may take a bit of time for a wide usage and acceptance, I foresee these legislative bodies eventually yielding in. Imagine even in some less developed markets we continue to see them slowly embracing crypto and a rise in awareness and sophistication by both users, technocrats and crypto entrepreneurs.
Stopping Libra now is temporary, new and similar projects will image somehow.