Turkey is probably the least Islamic country of all of them, including more pro-American which are savagely Islamic yet has more respect to the flag.
I personally believe that every flag of every nation is sacred to some degree and in no way a subject to humiliation.
Maybe it was, but Erdogan has been steadily moving to a more and more islamic state. He has purged the military of senior officers who would have put a stop to this (following with the intent of Ataturk), has been brazenly anti-Israel, is trying to play both sides against the other with the Kurds and ISIS. He has openly stated that democracy is only a means to a political end (although he has not stated what that ultimate political end is). For our interests, we want to maintain our presence at Incirlik (strategic). What else we need Turkey for, I don't know.
Not under Erdogan.