I believe that common carrier applies to platforms, not just the infrastructure of wires. These platforms could not exist without the large privilege given to them I'm immunity to the illegal content they serve up.

The problem is that these platforms have it both ways. They can censor entire political parties, yet play dumb and cry immunity "we're just a platform" when there's literal illegal content that makes it's way to their public hosting.

Once they censor based on content, they should lose all until and be considered a publisher of that content. They're no longer a passthrough, they're now actively working to manipulate opinions