I don't think this is good logic. If something appeared in Russian or Chinese newspapers that the state didn't approve of, then several reporters would turn up

I don't think this is good logic. If something appeared in Russian or Chinese newspapers that the state didn't approve of, then several reporters would turn up dead. You can hack Putin's Political Party, or some of his candidates in the lead up to an election, but it's not going to have the same effect of Putin hacking En Marche because En Marche is fighting a free and fair election, and Putin manufactures election results. There is no misinformation you can pump into a Russian election that will result in Putin losing an election because the election results are devised by Putin in the first place and any opposition leaders turning up with Novichok in their system. America may do bad things, but these specific bad things generally aren't actually an attack vector on China or Russia.