Their employees are mostly American, as I originally stated. Their engineers are not.
Huawei USA is almost certainly majority controlled by Huawei China, whereas Zoom's Chinese subsidiary is almost certainly majority controlled by the US parent company. Hence, Huawei is a Chinese company for practical purposes (the people calling the shots will go to jail if they don't do what the CCP wants) and Zoom is an American company (the people calling the shots go to jail if they break American law, and are mostly out of reach of the CCP).
Huawei USA is almost certainly majority controlled by Huawei China, whereas Zoom's Chinese subsidiary is almost certainly majority controlled by the US parent company. Hence, Huawei is a Chinese company for practical purposes (the people calling the shots will go to jail if they don't do what the CCP wants) and Zoom is an American company (the people calling the shots go to jail if they break American law, and are mostly out of reach of the CCP).