It’s inconvenient enough to suggest most western hackers attacking western targets would choose something else if they had the option. Thus either China’s cyber security is terrible and or these attacks are coming from Asia.
And as an attacker you couldn't care less about latency when you schedule a job of scanning bunch of ip addresses for vulnerabilities to one of thousands throwaway hacked home pcs in your fleet.
Latency doesn’t prevent such things from working, but your better off hacking local resources and then using those resources to scan locally. So all things being equal either there’s a huge surplus of especially vulnerable Chinese machines or a surplus of Asian hackers.
To be clear there could just be a huge surplus of easily hacked Chinese machines, but that itself would be noteworthy.