That's not how international relations work though. If you tell people what's up, they will react and show you what's up as well. Countries don't just eat stuff up.They will reply in kind. Especially so when you deal with a China that sees itself as an equal on the world stage.
You can't just bully around actors like China and expect to get away with it unscathed.
Trump may have had Russian hackers on his side, but let's see how he fares against Chinese hackers.