Because US spies in China saw that Tictok is/has been utilized to track military personal on US military bases, including location tracking of images of military and infrastructure. Much of the rest of the world has seen this done to them also. Think about this - If it was 1942, Alexa was Nazi party tech and you were Jewish, would you have an Alexa in your house?
XI has made his global goal clear. If you don't want to resist hm, learn to speak Chinese.