They're silent.

I don't know where Trump got the idea from. Perhaps he thinks they work like fans?

They're most certainly not silent! If you're standing right under one, you can hear it over car traffic and the breeze! (Well, unless the wind is blowing really hard: then the wind might be louder than either, considering the usual minimum distance between wind turbines and roads.) Whatever will you claim is silent next? Refrigerators? Lightbulbs?