Do other countries put US hardware and software companies on blacklists for their involvement with DoD? If so, then I think quite a few major US tech companies would be unable to do business outside the US and Europe.
I guess you have not been following the various EU rulings that say that EU citizen data must not flow to U.S. companies because it could be collected by U.S. intelligence services. “Google Analytics Ruled Illegal” would be a typical headline.
The US has ITAR. If you have certain government contracts you are prohibited from selling products or providing access to certain foreign nations (blacklists), or a complete export blanket ban.
For instance, I recently started investing in an excitingly expensive hobby, night vision. The tubes in those things are so heavily restricted that I cannot even let a foreign national touch them, technically. Which makes it interesting considering my girlfriend is a Tunisian foreign national here on a work visa, so technically I cannot show her my cool new toys I spent thousands of dollars on.
China has just about banned any foreign software services?
They can't ban the hardware, of course. While in the US finding a Chinese part in military hardware is a reason to stop the line, they rely extensively on US parts.
We got some recent movements in trying to basically say "if it's US company it doesn't comply by GDPR", because US laws require companies to snitch on demand