Do you understand the difference between the meaning of a word, and the identity of the referent of that word?
If I say that the English word God, the Hebrew word Elohim and the Arabic word Allah have basically identical meanings, that is a linguistic fact. Thus Arabic Christians, including the Copts presently being attacked in Egypt, use Allah in their services and Bibles to refer to the One True God.
I am not saying the Allah worshipped by the Copts is the same Person as the one worshipped by the Muslims, only that the word is the same. And that it means basically the same thing as God, Deus, Elohim, Theos, and Dios.
You are wrong and we are done.