Presumably if it's a serious attack by a non-state actor, Google's lawyers are on the job in the relevant state(s) getting police involved, for whatever that's worth.
In the state actor case, there's little or nothing they can do to make it stop happening, hence the special warning.
It's also a high-profile jab at the unnamed state actors, which is nice.
I assure you that the grandparent is misinformed, the chance of google's lawyers and/or the police being involved if some individual is sending you targeted malware (aka spear phishing) is essentially 0%.
AFAIK you do get warned if Google thinks your account has been compromised by normal pishers and what not. This is just a more detailed message that I'm sure most people will never see.
In the state actor case, there's little or nothing they can do to make it stop happening, hence the special warning.
It's also a high-profile jab at the unnamed state actors, which is nice.