Earlier quoted context omitted.
Because all this "national security" is really about trade not national security. Trump declared national security on steel, cars and pretty much any important industry that US didn't lead.
Incorrect. While the Trump administration is more enthusiastic about aggressive intervention in commerce in general, the recent sanctions are the culmination of over a decade of bad behavior by Huawei, recognized by many countries: https://en.wikipedia.org/wiki/Criticism_of_Huawei
As far as technology is concerned US is using its corporations(Apple, Cisco, microsoft etc) for espionage as well so there is nothing new here.