Russia has been selected as the scapegoat because its one Americans don't need much convincing to blame. The two have been rivals since then end of WW2, and even during it.
Remember, the media talked about how it was IMPOSSIBLE to hack the election when Trump was being destroyed in polling data. I recall the countless articles that were basically "No Trump, the election can't be hacked, deal with it." Then the media completely flipped their position after the election when the woman they dumped billions into lost. Suddenly the election could be hacked, and it was the Russians! If Russia did anything, all they did was make it look like they did something but did nothing. Like a thief who would break into your house, mess it all up, maybe hide something, and then leave. If they did anything, it was to keep the two parties hating each other and to keep Russia a US rival.