There's also a whole bunch of very good reasons for not having one. We've had this discussion already a few years ago (so I don't really feel like rehashing the same arguments again, but you can easily look them up, IIRC it was about Google+ not Facebook, but the reasoning is exactly the same).
I can't really tell from your comment history if you're from the US or EU, but I'm going to guess the US.
Your view on what should be platform's rights, kind of implies there is supposed to be as little regulation as possible.
And the problem with that view is, if you ask people why they are still using FB, given the knowledge of what they do with user data and privacy, the most heard excuse is that they feel they have little choice to use an alternative!
If you add to that the consideration that it is in the very nature of social network effect that this choice will be diminished to a singular monopoly (a social network is not very useful if your friends/family aren't on it), then you have to admit that the power in "people's right to not use a platform" is absolutely miniscule compared to your desired "platforms right to do what they want".
And it is that very imbalance, what regulations are intended to solve (or at least push somewhat towards fairness).
When someone in the street is speaking aloud, then you can't go to them and demand them to reveal their name, even if what is spoken is against the law. You can call the police and they can determine the name of the speaker. The internet is not a lawless place.
