The current tech giants will adopt what they can control and will crush whatever they can't. Either technologically, fiscally, politically, legislative or socially.

How would an ungoverned corporation be less evil than one subject to democratic laws?

Facebook is not subject to democratic laws as they ignore most of them and only follow certain ones from a small group of about a dozen countries.

A decentralized organization is governed by the public which is more democratic than other systems that exist today.

Are there good cases of Facebook ignoring democratic laws? I've never really heard of Facebook doing anything that isn't in violation of laws (United States laws at least, I cant say other countries). For the U.S. the laws just aren't there yet to put the right restrictions on Facebook

This can only happen if we have strong anti-monopoly measures in place to prevent big tech from artificially smothering the competition in the crib.