I heard this stupid arguement about 10 years ago from a Byzantine priest who said his Eastern European visitors were SHOCKED to see an American Flag on a pole behind the altar railing. So, the hammera$$ took it away and put it in the back of the church. Promptly, quite a few members of the church (I included) walked out. When he followed us and asked us why we were leaving, we told him that if it weren’t for that same flag that the Easter European visitors were degrading, they be forced members of the Nazi party or would have been put to death.
I don’t know about the others, but I left and never came back.
We don't have a United States flag inside our church.
Ours is on a flagpole outside for all to see.