Facebook will write its own regulations, as most regulated industries do, and write them in a way to protect the incumbents and harm competitors. New regulations would likely act like wet concrete poured over the market – and would then solidify and entrench horrible companies like Facebook.
Like I have been saying 🙂

But the danger is that those same requirements could be much more onerous for a tiny upstart company to uphold. Without much cash or enough employees, and with product-market fit still to nail down, young startups might be anchored by the weight of regulation. It could prevent them from ever rising to become a true alternative to Facebook. Venture capitalists choosing whether to fund the next Facebook killer might look at the regulations as too high of a price of entry.

Source: Regulation could protect Facebook, not punish it | TechCrunch
And this is why Zuckerberg is suddenly open to regulations. He knows that regulations will quiet the storm but do nothing to stop his global spying operation.