With Mark, saying and doing are two completely different things.
Example: "Helping poor people in third world countries get online" turned out to be: "Deceiving poor people in third world countries into using something called 'Internet' that's actually 'Facebook with apps', and depriving them of real online access."
That whole thing ended up being an attack on the free and open web.
"Share with friends only" is short for "Share with friends and FB employees and PRISM-subscribers while we decide who gets to see what you shared."
I could go on for quite some time.
Somehow all the "help" he tries to provide ends up increasing his control over other people's lives while disempowering them.
The last time I checked, using Facebook was entirely voluntary. The existence of it takes away nothing. You have everything you had before, and also the option to use Facebook or not. There's nothing disempowering about that.
Thankfully you're right, Facebook is not—yet—capable of disempowering the entire world by its mere existence. But it does disempower its users, and the more users it gets, the more it disempowers even those who don't use the system thanks to those "network effects" that everyone is after.
It's not inconceivable that at some point some country (perhaps very close to home) might decide that having a Facebook profile is mandatory in order to operate a business. With their Real Name™ policy it might even be useful for registering citizens. You can see this already happening on a smaller scale with some companies requiring Facebook login in order to use their product or service. I see others calling Facebook a "public utility", seemingly unconscious of where that road leads.
Sure, you can say all of that is still "voluntary". You don't need to use that product and you don't need to even be a citizen of the United States. You could move to some part of Africa where Facebook has not yet commandeered the social infrastructure. But, somewhere around that point I think most would agree that the word "voluntary" ceases to have any real meaning.
The key to refraining from interfering with other's lives is to refrain from interfering with other's lives even that other is trying to interfere with us. Or we would end up just like them.