that feels like obfuscation fallacy, because I have no idea what you are proposing in practice.
deciding when free speech crosses a line into a nexus to criminal activity like fraud, libel, conspiracy, incitement, disturbing the peace is hard. deciding when it crosses a line into simply violating community standards designed to further the goals of the community and forum owners, and violates the right or expectation of others for civil discourse is also hard.
it's a bias-variance problem, you can ban the n-word but people find other ways to make people unwelcome, a demagogue can say they are just asking questions when they are pretty plainly trying to start a riot and get people harassed and swatted and feel like they will suffer violence if they disagree.
I don't see anything inherently wrong with using AI tools to help make decisions like that. all that AI that controls what shows up in your feed is already implicitly doing that. inherently when one guy thinks he's making a stand for free speech, someone else is going to think he's coddling extremists who are strategically flooding the zone with bullshit, driving out civil discourse and worse.