Maybe they knew we'd think it odd for Russians to speak with a Russian accent so they did it anyway to trick us.
"Are you the sort of man who would put the poison in his own goblet? Now a clever man would put the poison into my goblet, because he would know that only a fool would drink the goblet given to him. I am not a fool, so clearly you wouldn't do that. But you must have known that I was not a great fool, so I mustn't drink from the wine in front of me!" [0]
Yeah, pretty much. Except no poison drinking was involved here. Unless it was the NSA that did it. And of course, this was all old stuff, so it wasn't really very poisonous.
But really, really, really. There's just no way to know.
Almost certainly what a Russian disinformation campaign would include. But you cannot easily hide motives and attack patterns. These kind of campaigns scream Russia, no one else in the world operates like them or could operate like them. Almost everyone in the intelligence circles include Snowden agrees they are Russian. Smells like a duck, quacks like a duck...
It's not easily copied, that's my point. The MO of this campaign (and others) isn't easily done, which is why it's easy to narrow down suspects. There are only a few possible intelligence agencies that could do something like this and only Russia has the motive.
You can't have it both ways. If it's so easy to spot, it's easy to emulate. And how can you rely on motives? What you have is evidence, from which you infer motives. When there's so much avowed certainty with such subjective evidence, one must suspect an agenda.
I'm not sure that's fair to say, you can recognize patterns, spot and attempt to emulate something, but that doesn't mean you actually are doing it correctly. Lots of militaries try to emulate the US military but cannot. Operational expertise, tempo and other factors are really difficult to nail down and something that's developed over time and with practice.
I think what you're saying is fair, but the only nation state actors with the right combination of evidence, agenda and motives would be Russia. Who else?
"Are you the sort of man who would put the poison in his own goblet? Now a clever man would put the poison into my goblet, because he would know that only a fool would drink the goblet given to him. I am not a fool, so clearly you wouldn't do that. But you must have known that I was not a great fool, so I mustn't drink from the wine in front of me!" [0]
[0] https://www.youtube.com/watch?v=U_eZmEiyTo0#t=1m20s