First of all, China likely has far less cyber surface area than US. Which means US will suffer more damage in the event of a cyber war.

Secondly, it is dangerous to suppress cyber attacks via negotiations, appeals and threats (as opposed to technological means) because then we'll be in the dark as to their capabilities and our exposures, and in the event of an actual war we'll be unprepared and they will cripple us easily.

Instead, we should do what companies such as Google and recently United Airlines have done: reward hackers who find vulnerabilities. Then disarm the opponent by fixing our vulnerabilities as quickly as possible.