Because Facebook would be completely fucked if they were caught doing it. Even if by some miracle the US government didn't do something about it at the very lea

Because Facebook would be completely fucked if they were caught doing it. Even if by some miracle the US government didn't do something about it at the very least the EU would. That's not even getting into the mass user exodus it would trigger. Something I'm sure marketing teams for other existing services would gladly take advantage of. Facebook is in an amazing position in terms of market share and leverage but they're not invincible. I would wager that if they were caught doing this Facebook would have a new CEO and possibly a mostly new executive team in a matter of weeks or even days. I think it would trigger the introduction of some kind of third party auditing program to ensure it would never happen again. There would be ads running everywhere trying to make amends with the user base. Even if I knew nothing about technology I would assume it was something I didn't understand before I assumed it was the company doing something so utterly stupid.