What is being disputed is that making it look like it came from a Russian intelligence officer specifically, as opposed to from some random infected machine somewhere, is easy. I see that you're claiming that if you set up a botnet and start infecting people and wait, you'll eventually get someone who works for a bank or someone who works for the military, sure. But what are the changes that you'll find someone who happens to work for the specific intelligence agency that is widely suspected as being the actual perpetrator?
Are you claiming that lots of botnet operators happen to have infected so many machines that their chance of being able to get to the machine of an employee of any government agency in the world is high? That the average GRU officer has hundreds of RATs in their home from hundreds of bored teenagers around the world?