This is absolutely not true. There's so much wrong with that argument and how it applies to Facebook it's hard for me to provide decent criticism, but I'll try anyway.

Facebook is not provided 'for free'. Nothing is. Facebook is provided to users in exchange for their personal and social data. Facebook is also not really 'a thing'- it's much more complicated than that. The worst part of your argument is that this criticism of free software also holds true for proprietary software- there are plenty of nonfree services which do the same thing. More generally, 'free' software as you define and apply it is not a useful categorization of software to make. What about freemium services? Are those free or do you pay for those? Whether or not you pay in currency for a software license is not really meaningful in the discussion of user freedom. I recommend you actually do some reading on the topic of software freedom and Facebook before you go spouting completely unfounded aphorisms online again.