Turkey was definitely secular for almost a century, but it's getting to be a stretch to describe them that way now.
Also, can't one describe a country with a heavy religious majority as a country of that religion? It doesn't mean their government is a theocracy. So in 1950 Turkey was a Muslim country with a secular government.
I dont think it would be fair to call a country with any particular religion majority that way. Most countries have a majority religion of some sort. Many countries can and should be described as secular, especially in the west.