> Then how come I don't see Zuckerberg and Sandberg behind bars yet?

Well, because SESTA hasn't gone into effect yet. You can bet once it does there will be at least private civil cases against Facebook. Public, including criminal, ones might take until they've got precedent from smashing less well-funded defendants, but they'll come, too, especially (even if Facebook takes drastic action now to prevent future liability) for past cases under the retroactivity provisions (which should be constitutionally problematic for criminal cases, but not so much for civil cases.)

There is no ticker symbol for backpage in their portfolio.

Laws like this are selective in nature.

That one's simple: bribery.