Some think that every person called a Muslim has the same view of everyother Muslim, so if they find a certain practice in one Muslim country, thismeans all Muslims hold the same viewor the practice must automatically be a part of Islam and/or The Quran.
Saying the above is like saying all 1.7 billion Christians in the world have the same view on everything. Of course, we can all see the absurdity of this way of thinking. Islam, like any other faith with a large number of followers, has differing views amongst its followers.The most obvious case of this is that no two countries ruled by Muslimshave the same system of law. Within Islam there are different sects who have different beliefs, some of them are minor differences, some of them major. The two main groups of Muslims (in terms of numbers worldwide) are Sunni and Shia. Sunni Muslims are the majoritygroup, accounting for perhaps 80 to 85 percent of Muslims worldwide; Shias are the minority (however Shias form a majority in some countries, e.g. Iraq and Iran). There are also other sects, such as:Wahhabi, Suffi, Ahmadiyya, others etc (see link below). However, even in each sect, views can differ, so not everyone has the same view on everything.
All Muslims however accept TheQuran (sometimes called Koran) as the final divine revelation to humanity. Itshould be noted that within The Quran itself, dividing ones faith into sects is strongly condemned and emphasis is placed on unity and what we have in common rather than division:
The people used to be one nation (but then differed), so God sent the prophets as bearers of good news and warners, and He sent down with them the Scripture with the facts so that they may judge between the people in what they were disputing. But after receiving the clarity, the people disputed in it due to animosity between them. And God guided those who believed withHis permission regarding what they disputed in ofthe truth. And God guides whoever He wishes to a straight path. [2:213]
...and do not be of those who set up partners, or like those who split-up their system, and they becamesects, each group happy in what they have. [30:31-32] Say, “O People of the Book! (people of previous revelations) Let us come to a mutual agreement, that we shall serve and obey none but God. That neither shall we ascribe divinity to anyone beside Him, norshall we take human beings from among ourselves as our lords beside God.” And if they turn away, thensay, “Bear witness that it is we who have surrendered ourselves unto Him.” [3:64]
Abraham was neither a Jew nor a Nazarene, buthe was a monotheist who submitted; he was not of those who set up partners. [3:67] And do not argue with the people of the Scripture except in the best manner; except for those who are wicked amongst them, and say: “We believe in what was revealed to us and in what was revealed to you, and our god and your god is the same; to Him we submit.” [29:46]
O mankind, We created you from a male and female, andWe made you into nations and tribes, that you may knowone another. Surely, the most honorable among you in the sight of God is the most righteous. God is Knowledgeable, Expert. [49:13] Nor does he order you that you take the angels and theprophets as patrons. Would he order you to rejection after you have submitted to God? [3:80] They took their Priests and Monks to be patrons besidesGod, and the Messiah son of Mary, while they were onlycommanded to serve One god, there is no god but He, be He glorified for what they set up. [9:31]
“And this is your nation, one nation, and I am your Lord so be aware.” But they tore themselves into disputingfactions, every group happy with what they possess. [23:52- 53] In matters of the faith, He has ordained for you that which He had enjoined upon Noah - and into which We gave thee[O Muhammad] through revelation as well as that which We had enjoined upon Abraham, and Moses, and Jesus:Steadfastly uphold the faith, and do not break up your unity therein. Intolerable for those who have set up partners is what you invite them towards. God chooses for Himselfwhomever He wills; He guides to Himself those who repent.
A good example of differences in view, is when a "fatwa"(religious opinion concerning Islamic law) is issued by aninstitution or scholar, it is not actually binding on anyone.