Because Turkey in its current state is leaning towards radical Islam which is very dangerous for the stability of Europe. Turkey tried to play dirty with Russia also but Putin told Erdogan to go fuck himself right? Do you honestly believe that Erdogan cares about NATO or USA? He is probably tired of licking everyone's asses that's why he staged that fucking coup so he can gain control of the secular Turkish army which is actually one of the most sizeable armies in the world. When he gains control of the army he won't care about his friends in the White House nor about NATO because radical Islam doesn't care about anything but Muslim superiority.
I will quote what radical Islam means for you:
While professing unwavering faith in a transcendent deity, radical Islam is a militant, politically activist ideology whose ultimate goal is to create a worldwide community, or caliphate, of Muslim believers.