> so they can provoke political intervention that they can comply with, but few others can.

See Meta et al complaining about Section 230 of the DMCA. Meta would be entirely able to moderate in an environment where mass scale moderation/censorship would be required to prevent a host's liability for UGC. Almost no one else would be able to do so.

That means no upstart could possible come along to dethrone Meta as they did with MySpace. It would also be impractical to run a FOSS social network (or forums). Meta could literally just have bots sign up on a FOSS social network until its DAU count ran over the statutory minimums to be subject to UGC liability.

Regulatory capture is a de facto ban on competition in a market.