This is the "it is this way; therefore people must want it this way" argument. It ignores the power of money to manipulate through advertising (or, in the general case, of power to coerce).

To take the specific example of FB, most people don't want to be tracked and advertised to, they just want an easy social space to interact with their friends and family. Sure, they'd probably prefer an ad-free, non-tracking version of FB, but not if it costs them much effort. So, FB's growth hacking, advertising, and critical mass have pushed millions of people into something they themselves would consider sub-optimal (assuming it was explained to them, ofc -- many are plain unaware).

On top of that, the average user simply does not have the knowledge to make an informed decision. Not about what's technically happening, and certainly not about what the long term consequences will be, although arguably no one knows about that.