It has to be treated as criminal negligence when a platform applies its 'Terms of Use' or rule of conduct, selectively.
I think that will solve the problem.
Today, HN or Twitter can, selectively, diminish visibility of pro-conservative content and posts, while not applying the same scrutiny to the other side.
They can sit there and claim neutrality, ask for 'evidence' and so on.
But really, they are the ones that should be convincing courts that they were not partial, biased or selective in applying their Terms of Use.