I think there needs to be careful consideration about the burden of proof. If Chinese government accuses a US company of illegal activity, Chinese government should bear the burden of showing the evidence. It should not be the accused US company's responsibility to prove its innocence.
There also needs to be careful consideration about associating country of origin and a company. US government's spying program all over the world is well known. Nonetheless, I do not think it is fair to use that as an excuse to ban a US company.