I am not trying to pose some profound question. I am genuinely confused by this.
It's all about what ultimately happens to the information harvested. If it's some kids in mom's basement doing it for lulz, that's not very concerning.
But, presumably, Russian hackers, even if not actual Russian government employees, would pass on useful information to their government. Even if non-classified, that could be very damaging to national security.
From the article, the attacks were relatively sophisticated. Which makes it more likely that "state actors" were involved. The article also claims that the two most common state actors are Chinese and Russian, and the fingerprints of this operation pointed more to Russia than China.
YMMV. As you say, "attribution is a very difficult and often impossible process".
Because of this, there is no difference for national security whether Russian government hackers did it, or anyone else. The only piece of useful info is that the systems were hacked and how they were hacked. The attribution is just for show (and as always in these cases, not very reliable either).