We just visited Turkey recently. The people were very polite and courteous. We had a greatime. Our guide told us to stay away from the politics. The tee shirt----wear another. Don't attract attention with that t-shirt or one bearing the US flag. This is not the day and time to attract attention when you are overseas and a tourist.
I am a tad confused. I can understand not wearing something with US flag in certain countries, but why would it be a problem to wear one with a Turkish flag in the US? Yes, some people get their politics mixed up in day to day life, but come on.