I agree: sites hosting those like button are the ones we should blame hard, because they should protect their visitor's privacy. It's very easy for any web site to implement "safe" social buttons but they don't care for most.
I don't blame FB when they try to use any way they can to gather data. This is their business. I do think though there are some boundaries nobody should cross. Because there is no good technical answer yet does not mean we should just let them do anything. That's my opinion (and this is only an opinion). The french law set some of those boudaries in a way that seems balanced to me.
The french CNIL (I'm french) has ben setup long long time ago (back in the 70's) to ensure data privacy law is applied. They go after FB because FB violates a french law. In france, this is unlawful to collect data without signing a consent form. You also have to provide a way to remove any data to end users, on simple request. There are 5 ou 6 key points like that where FB violates the french law.