the method of enforcement should be to arrest the perpetrators
To do that, you have to know who the perpetrators are, which is routinely impossible.
This isn’t a hypothetical situation, we are living in a world where servers are kicked off the internet, SSL certificates are revoked, vast quantities of emails are deleted without even sending them to a spam folder, lemmy communities are closed down, etc.
In a perfect world, none of that would be necessary and we could simply send the perpetrators to jail. But we don’t live in a perfect world. We live in one where censorship is the only option.