It doesn't have NSA backdoors in the design so it's unacceptable for domestic use and they don't want it to take off for foreign use because then they can't spy on other countries. (Same rationale behind banning Huawei, never was about Chinese backdoors, was about lack of NATO backdoors that was the issue and always will be with any Chinese products).

Even assuming a lack of built in backdoors, the west controlling the companies responsible for these things mean they can sit in the pipe of their security disclosures and pick out zero days disclosed to the company, exploit them against enemies first before those enemies even know it. If they're Chinese companies they can't do that.

There's zero evidence China behaves like the western bandits and hoodlums and plenty pointing to the fact China keeps business (selling you good working products) and spying (gathering intelligence) separate. They won't sell you a trojan horse, they'll just hack you, having no particular advantage because of secret knowledge or back-doors. Which is the way things should be in the type of world the west claims to be for in their alleged desire for free markets and free trade.