I don't think this is done on purpose at the state level in Russia or China, It's just that sometimes government don't pay attention to those who do it if this is done in relation to somehow unfriendly countries. But the US also uses hacking for hostile purposes. For example, Stuxnet and some other cases. Yes, it's not ransomware, but the difference is not that huge. Western-backed countries like Ukraine are also doing the same. Anyway Just use Linux and you'll be fine for a while.
Foreigners won't go to Russia to file a complaint to police. Without a complaint, there is no reason to investigate anything. I think this is the explanation.
Also it is 100x more difficult to make Russian pay for something, including a ransom. So attacking fellow Russian is a high-risk, low-return move.
In the past US LE has tried to work with Russia to arrest ransomwarw groups but it didn't work out. Russia demands extradition of political prisoners or some such in exchange so it falls through.
When Russia arrests a hacker they're turned over to the GRU and told who to target. Western governments use hacking for intelligence gathering not economic warfare. The ochko123 fraudster was very connected with the Russian government, it's state policy.
