It's not unheard of to apply some occam's razor just in case while keeping misdirection in mind. Even masterminds aren't perfectly rational actors that cross all their t's.
I was always surprised to see security researchers confidently attributing some attack to a specific group based on easily falsifiable things like localization, alphabet, time zone, coding "style", specific targets, etc.
Even if researchers can undeniably link one attack to a certain group (like when they publicly take responsibility) and can label their style accordingly, all those indicators become at least semi-public. If the researchers have access to them, so do other other actors who are free to fake or imitate them. The confidence is probably more for the media reporting.
Looks a lot better than getting pwned by some jackass American teenager. So if the attack came from a Russian IP, or used some Cyrillic characters or something like that, there's a "face saving" incentive to take that probable misdirection at face value.
- real attacker doesn't want to get caught
- victim doesn't want to admit being pwned by a script kiddy or petty criminal
- military-industrial complex needs foreign threat inflation to stay in business
- media loves the intrigue
The pushback would come from the foreign state being falsely slandered, but they never get a say anyways.
I generally agree with the quip about American patriot actors, mostly.
For instance, a malicious actor, of even basic sophistication, coming from a Russian ip and occasionally using Cyrillic and missing grammatic artcles is probably not Russian. Similarly a malcious actor with a pseudonym including the term patriot, coming from a US IP and using terms like howdy probably is not American.
False attribution is a core lesson in malice 101.