I care deeply about what is true and what is not. No matter who you are or what you believe, you cannot say Muslims are atheists without being completely and utterly wrong.
Definitions are definitions. There is no acceptance by me of misuse of the language. I would hate for someone who doesn't know better to read misinformation here such as "Muslims are atheists" and go away thinking it is the truth. Allowing people to state things which are not true and not call them on it (regardless of their beliefs) does no one any good.
To what end. Any person that wants to understand a definition, will inevitably use a dictionary. When we speak of a principle or thought, sometimes it is hard to convey without using words out of their established norms. Usage of words in a religious environment will naturally diverge from absolutes. I am sure everyone is in agreement on the definition of the word. The concept is the bone of contention.
By definition Muslims are monotheist in their belief of a God. The divergence and rationale in usage of the word is the concept: belief in a false God is equivalent to belief in no God, thus atheist. So it's a believers conclusion, rather than a debate over the definition.
I can see both sides of it, and I don't see either side adjusting their view on the matter.