National fiber optic communication network is used by the military, banking system, government agencies etc. All of them are strategic importance no less than oil. Remember Snowden's revelation? Give you another hint, three (or four) years ago I heard a colleague from China saying that all telecom trunk routers (from Cisco) in her province were replaced by Chinese made routers without American processors, so you should know that a chip is no less critical as a barrel of crude oil. Rice or wheel seeds are even more critical than oil.
see my previous post. again its gone back to whether CCP directly support it or its a company decision. also do you have list on what ZTE sold to Iran, smartphone or actually iran network infrastructure.