Why is Huawei banned in the USA?

It just so happens that Huawei is only unofficially banned. There's a big difference between unofficially banned and officially banned.

Wherever the U.S. government has influence, at home and abroad, Huawei market access is blocked. But there is no comprehensive bans except for government and military contracts.

It’s true that government agents meet with hundreds of Huawei’s customers in order to brief them on the dangers of doing business with Huawei. These “briefings” are widely seen as blatant intimidation and few companies in the wireless industry have maintained relations with Huawei after sitting through an uncomfortable meeting with U.S. G-men.

Recent developments include:

• AT&T and Verizon where both bullied into exiting distribution deals with Huawei after Huawei spent millions in logistics and marketing but only one day before distribution was to begin.
• CFIUS now disallows any U.S. acquisition by Huawei
• The FCC now makes billions in US subsidies off-limits to any company that does business with Huawei.
• Independent electronics distributors such as Best Buy have bowed to pressure and now refuse to carry Huawei devices of any kind.
• Eastern Oregon Telecom and LHTC Broadband are being coerced to swap out already installed Huawei infrastructure.
• U.S. diplomats have been busy abroad killing Huawei deals in Jamaica, South Korea, Australia, the Balkans, well, everywhere that U.S. influence and an airport exists.
• Western Mainstream Media has been destroying Huawei’s reputation by airing reports that the FBI, the CIA, the NSA, the Department of Defense, and so on, are all issuing warnings that Huawei devices are spy-gear and a threat to national security.

So while there is monumental resistance against Huawei, there is no official ban