He didn't force people to use it, but he lies of how it works, it's not transparent or clear. People are responsible also for using it of course. I didn't wrote we should have everything for free. But FOSS is better and more ethical than proprietary software.
What's there to lie about. It's an ad-based business model. To sell effective ads you need to target the right people which requires data...
Does the average Joe reads all the contract when signing up to Facebook? Plus users can't read Facebook code? Why not make it FOSS? What's sold is not what it really is. Even if most people knew better they would still use it, but that doesn't make it less evil and unethical.