If the FBI is going to make the broad statement that China is hacking the USA, it'll have to back that statement up by evidence presented in court against individuals the FBI has investigated for hacking into US companies/government orgs.
But that is not relevant to point that Chinese state media (which is in a way all their media, like becoming in Russia now) is wrong and lies regularly but will never undermine the cult of personality at the top of the government that owns it by admitting the lies.
To deny that you need to go all tinfoil on me and say most instances where they lied is made up by the West. Like idk Tiananmen didn't happen or whatever. If you believe that then sure.