Fair enough, however, depending on what brand of Islam they subscribe to, women in many Muslim countries do wear the full burkha rather than just the hijab which only covers the hair. When I was in Syria during the 1980's, women completely covered in black burkhas were a common site even though the government at that time was secular. But you are correct, the government of Iran does not require women to hide their faces. Some of the more extreme factions fighting in Syria do.