But you're contributing to HN which is owned by VCs with increasingly aggressive political postures (which we are not allowed to discuss on here) who could pull the rug on us whenever they want to.

The problem is that the n^2 stickiness of social graphs makes competition impossible when they scale into the millions. All the value is created by the users but accrues to the network owners, and then the owners are able to abuse and manipulate the networks as they see fit without repercussion. I think the ideal model for social networks is that they would be owned by benevolent nonprofits, but besides wikipedia VCs were able to capture every important social network of the Web 2.0 era.