If Theymos wanted to, he could come up with a list of things that are and aren't acceptable. It might not be easy, and it might not please everyone, but he could do it instead of doing nothing. I mean, that's what laws are--they're written rules describing behavior that isn't acceptable. Lawmakers don't throw up their hands at the complexity of the legal system and decide to not prohibit certain things as a result.
Once you start censorship it opens up a whole new can of worms.
If you censor some scams but not others it can provide a false sense of security.
Banning copy-pasting is not censoring because they have nothing
unique to say.
It is also a matter of "proof" and "liability". Copy-pasting when caught is fairly clear cut.
Once you start censoring scams you are accepting some sort of responsibility for the safety of the users.
The whole bitcoin thing came from the Cypherpunk movement - which tends to have a free speech and libertarian viewpoint on life.
Once you start censoring it very quickly turns into over-reach.
The reality is that most users that get banned probably re-incarnate as another account anyway.
A known & tagged scammer is better than an unknown & untagged scammer.
Lawmakers often over-reach. The powers they give their "henchmen" often affect ordinary citizens. (I'm not only talking of developed democratic countries)
To make something illegal - lawmakers only have to declare it to be illegal. Lawmakers only pursue "crime" if it is in their self interest.
The average CEO salary is more than 531 times that of the average hourly worker.
Politicians get a regular pay rise -but for other Government workers it is "not affordable".
Some wealthy executives pay less tax than a laborer.
Some drugs with minimal risk are illegal - while other drugs with high risks can be prescribed by your doctor.
Euthanasia, and suicide are illegal in most countries - but the death penalty or "shooting by police" is not illegal in some of those countries.
Some large corporations pay no taxes without breaking the law.
Some legal action can leave an innocent person broke.