The "why not" would be because in some cases the outcome is worse. I agree that ISPs should be common carriers. I disagree that social media sites should be.

The "why not" would be because in some cases the outcome is worse. I agree that ISPs should be common carriers. I disagree that social media sites should be. To me this is analogous to "everyone should be allowed to travel on public property, not everyone should be allowed in my bar".