You seem to imagine that peoples' concerns about Facebook are in the context of a bilateral relationship.
I'm not a customer of Facebook. The customers of Facebook do not feel any obligation towards me, and I would like the government to force them to operate under more constraints.
In the ensuing 35+ years, a new anticompetitive situation has developed around different technology and different shared resources. Should we judge the solution to a problem by whether more problems of the same class arise independently for future generations?
It's simple: if you don't like Facebook, don't use it's products. It's not the proper role of government to interfere in private business.