1) whataboutism
2) citation needed
3) Even if both sides utilize propaganda, historically the scale of agitprop coming from authoritarian countries has been much greater. This is still newsworthy.
You can't even read most Western propaganda in China because the government goes to great lengths to censor narratives counter to offical views.
Depends how narrowly you define agitprop. If you consider everything that comes out of the American media/news conglomerates as propaganda, then it's orders of magnitude greater than the efforts of China or Russia.
The difference is that American media isn't owned by the government. Chinese media can't tell the government to "fuck off" if they don't want to report something. In the US they can.
You can't even read most Western propaganda in China because the government goes to great lengths to censor narratives counter to offical views.