I think it's more difficult than one imagines to ban Bitcoin's linkages to the existing institutional financial system. After all, it's not as if REvil or DarkSide are using Coinbase to trade their Bitcoin. If the United States shuts down all Bitcoin exchanges operating on its territory, but Russia does not, then does that have a meaningful impact on the usage of Bitcoin for cybercrime? It seems to me that all such a step would do is make the positive usages of Bitcoin more difficult while having only a marginal effect on the usage of Bitcoin for cybercrime.

Tenable, for sure. Effective at preventing companies from finding a way to pay a ransom (where the ransomers know it'll take them additional time to acquire the cryptocurrency funds)? Probably to at least some degree; I'm not sure exactly what the deterrence and enforcement statistics might be like.

But wise or ethical? I'd argue about as wise and ethical as classifying cryptography as munitions. Cryptography in general is certainly more broadly useful than cryptocurrencies, but strong cryptography also enables far more and far worse crimes than cryptocurrencies alone do.

And can you believe there isn't a law preventing US ISPs and network providers from shuttling traffic to or from known Tor nodes? At least 90% of it is obviously used for unethical and/or illegal activity, and it'd be tenable for ISPs to regularly null route public IP addresses they confirm Tor nodes were listening on. Sure, Tor has a few niche use cases like cryptography does, but it so overwhelmingly enables atrocious and criminal activity that it's an injustice no bill has been passed to fight it. Some people could still get around it, and I'm not sure exactly what the deterrence and enforcement statistics might be like, but it'll probably still help to at least some degree.

Governments that shield criminals are the cause here. Go after them rather than the technology the shielded criminals happen to leverage.