Evangalizing

There are Atheists in most Muslim Nations just as there are in every nation. However the Atheists in Muslim nations generally do not advertise their disbelief.

Contrary to popular belief  it is not a crime to be a non-Muslim in any Islamic Nation but in some it is illegal to convert a Muslim to another religion.  Atheists normally are not trying to entice Muslims to leave Islam and go unnoticed unless they make their  atheism a public matter.

While Iran is not Arab and  is Shi'ite, not Islamic it is viewed by most of the non-Muslim world as an Arab Muslim nation and they do have very harsh punishments for anyone suspected of being an Atheist. I think the Death penalty for an Iranian Teenager who stated he was an atheist on Facebook is the most recent example.

Shi'ite ceased being recognized as Muslims when they began following and venerating the Ayatollah who they believe is either the Mehdi or Jesus(as). They believe the Ayatollah Khameini has been alive since the time of Muhammad(saws) and just changes his body every now and then. The Shi'ite consider the words of the Ayatollah as being the direct words of God and have to be followed without question. All of these things are in violation of the first of the 5 pillars of faith all Muslims  must follow. They also do not say the Shahadah (There is no god, but Allah, Muhammad is the Messenger of Allah) They came up with their own version which is "There is no god but Alláh, Muhammad is the Messenger of Alláh, Alí is the Friend of Alláh. The Successor of the Messenger of Alláh And his first Caliph."

The only time we can say a person is not a Muslim is if they blatantly refuse to follow any one of the 5 pillars of faith. The Shi'ite are openly refusing to follow the First pillar of faith by refusing to say the Shahadah. and acknowledging they follow Ali

I am a little more Moderate than most Sunni as I do acknowledge the Shi'te as being Muslim but believe they are in grave error and living in shirk by venerating the Ayatollah.

Shi'ite are permitted to make the Hajj to Mecca if they give proof they have said the Shahadah. Which they usually do by publicly saying the Shahadah when entering  Saudi.