They have advisors that sure as hell know exactly what is going on here. This is a very naive view of how government works. Diplomates don't need to know what code is to make policy. Chinese bureaucrats certainly know that pissing off their biggest trade and manufacturing partner isn't good for their economy.
This was a very high-profile attack. Pretty much every intelligence agency in the world has notified their higher-ups on what likely happened and the hammer most definitely fell on this company. Chinese businesses aren't exactly known for their good corporate personas and generosity. See baby and dog poisonings and desperate reactions by the government like executing executives. On top of the everyday IP infringements and other cavalier attitudes towards international business norms.