It has nothing to do with spying and everything to do with protecting Apple and maybe even Samsung.
Samsung isn't a US company so...
And as you said "Sure Apple users probably won't shift to Huawei." If Apple users wanted a better/cheaper phone they'd already be buying the Android phones with lower prices and better features!
It's easy to blame "government." Look what's really happening though, Corporations are lobbying to have regulations like Net Neutrality removed so they can do whatever they want.
Samsung wants to protect their American market? They call up Verizon and offer them an exclusive deal to make Huawei phones get shitty signal connecting to Verizon's towers.