Because it is.
The existing status quo over cyberwarfare is untenable, and runs the very real risk of causing chaos if we don't tamp down on the usage of third parties for plausible deniability.
Most countries have offensive security capabilities directly under direct government control, but a number of them will also tolerate third party actors attacking a rival country so long as they don't attack the host country.
This is what LockBit (Russia), ChamelGang (either China or NK), Appin (India), etc has done.
Either everyone allows cybercriminals in their countries to attack other countries (and spark actual chaos in our entire internet infra that could escalate into actual violence), or all nation states agree to tamp down on third party attackers.
The Budapest Convention was the previous cybercrimes agreement, but most countries outside of the West that matter didn't ratify it. This meant terms of engagement over cyberwarfare weren't truly formalized, and a bad actor like NK or China could in good faith argue that a North Korean or Chinese cybergang did no wrong.
The brutal reality is that performative treaties like the Budapest Convention have no teeth, and a global Internet means that terms of engagement are needed for warfare, or the entire Internet splinters.
This seems overblown. The behavior you're describing has been present nearly as long as the internet has been globally accessible. It's an inconvenience and it means we need to do a better job securing systems against attacks, which is hardly the worst thing from an evolutionary perspective. Better that systems get hardened now to prevent ransomware than that they remain vulnerable until there is an actual war and an enemy state takes advantage of longstanding complacency.
> or all nation states agree to tamp down on third party attackers.
This doesn't happen even with a treaty, because not all countries will be signatories, and even the signatories can just ignore the provisions as they do with many other treaties. Corrupt governments deflect blame; "the attack seems to have originated from here but we investigated ourselves and found ourselves innocent" etc. Proving otherwise without local cooperation is close to impossible because the location of the originating systems is not inherently the location of the attackers. And, of course, corrupt governments are the places where these things are already happening.