All social media companies set rules for using their platforms, and they moderate content whenever those rules are broken. There's nothing wrong with that. It's allowed under section 230. But that's very different from selectively enforcing the rules and using algorithms to drive content in the direction you want it to go.
I have no problem with social media companies making rules against posting links to unverified stories. They have every right to do that to suppress misinformation. But they have to apply that rule uniformly to everyone. They can't remove unverified stories about Biden and allow unverified stories about Trump, because then they're taking an active role in shaping published content.
why do you think they are applying the rules systematically unfairly?
