Who is a Muslim? One way to decide is when the individual says he is a Muslim, recites the shahada, and lives more or less according to Islamic belief.

It is axiomatic that to be a Muslim you must believe in Allah by taking him as your unquestioning lord, accept Muhammad as Allah's beloved messenger, and take the Quran as a literal book of Allah and a perfect prescription for living.

The first of the Five Pillars of Islam is the shahada (Arabic, "testimony" or "witness").  The shahada is the Muslim profession of faith, expressing two simple, fundamental beliefs that make one a Muslim:

lā ʾilāha ʾillā llāh muḥammadun rasūlu llāh

There is no god but Allah and Muhammad is his messenger.

Another way – and, in my view, a more precise way – of deciding who is a Muslim is to use what science calls an "Operational Definition."  That is, for instance, if you claim that something has mass, then you should be able to document that claim by a set of operations – in this case, by weighing the object with some universally accepted scale.  If you claim that something extends in space, then a yardstick of a sort should give a reading about it.

An operational definition for Muslimness, or being a Muslim, goes something like this: anyone who, by his words or actions, promotes or empowers Islam, irrespective of what he may call himself, is a Muslim.  Muslims have operated by this operational definition of Muslimness for fourteen centuries, long before even the concept of an operational definition was invoked in science.

According to the cardinal rule of Islam, non-Muslims are kefirs (infidels).  The kefirs are fair game to be maltreated, plundered, taken as slaves, and slaughtered.  It just so happens that the followers of Muhammad, before rasul-ul-allah (the messenger of Allah) was even buried, started having disagreements among themselves about who was a real Muslim and who was a pretender and actually a kefir.  The house of Muhammad, in no time at all, splintered into sects, sub-sects, and sub-sub-sects and whatnot.  And each of these "real and true" Muslims started treating other Muslims as he would treat the kefirs, in obedience to Muslims' sacred teachings of the Quran.

In short, each sect was truly Muslim and used any and all means to further the true Islam it held, often including purging other sects whenever it could.

It is true that the vast majority of the victims of communism were people living in communist states.  Some 38 million Soviets were killed because of communism.  Tens of millions of Chinese citizens were killed because of communism.  That the victims of communism were largely members of socialist societies says a great deal about the ideology itself.  It is also true with Islam.  Muslims are the main victims of Islamic ideology.  Muslims killing Muslims has always gone on and continues to this day in places like Syria, Iraq, Afghanistan, and Pakistan.

"True Muslims" strap explosive vests and detonate themselves in a crowd of what they consider fake or deviant Muslims.  They also bomb each other at mosques, funeral processions, and marketplaces packed with women and children – all to promote true Islam and cleanse Allah's earth from kefirs, as they are repeatedly and emphatically instructed to do in the Quran.  By the way, apostates are included in this cleansing process.

Islam itself is a creed of an ignorant people in a primitive and barbaric age.  It is fixed in time and place; it harbors the ambition of taking the 21st-century world back fourteen centuries and ruling it by its dogma of violence, intolerance, injustice, and death.  Yet Islam is not only an obsolete vestige of a defunct era; it is an infinitely fractured belief that can hardly put its own house in order.  The numerous Islamic sects are at each other's throats; sub-sects and schools despise one another as much as they hate non-Muslims.  Hatred, not love, drives Islam.

The faith is divided into Sunni and Shiite sects with numerous sub-sects.  The divisions and contentiousness are so profound that members of one sect consider the other Muslims apostates, worthy of death.  The division goes back to the time of the Prophet himself.  Shiites believe that the enemies of the true faith subverted its chain of authority at Muhammad's death.  They claim that the Prophet, while on his deathbed, asked for a parchment to dictate his will and to appoint Ali, his cousin and son-in-law, as his successor.  The Shiites claim that Umar, an influential disciple and commander of the faith, declined the request, saying to the Prophet: hasbena ketab-ul-llah – sufficient unto us is the book of Allah.

Before long, division and infighting started in earnest and continues to this day.  Oppression of Shiite minorities in Saudi Arabia and Pakistan makes for only two glaring instances of this longstanding and irreconcilable intra-faith hostility.  The Shiite majorities in other lands return the favor to the Sunni minorities, as is the case in Iran and Iraq.

There is no such a thing as one Islam.  There are hundreds of Islamic sects in the same way that there are hundreds of diseases.  In the same way that there are no good diseases, there are no good Islamic sects.

In order to deal with an illness, correct diagnosis is essential to prescribe the right medication.  Hence, dealing with various sects of Islam effectively demands correct understanding of what they are, what they aim to do, and their methods of spreading their psycho-social disease.

Some Islamic sects are extremely virulent and deadly.  They must be dealt with accordingly.  Others are less violent and work their agenda in more subtle ways.  Even the latter types are far from harmless.  One and all keep to the Quran and pursue the same goal of dominating the world.

Conclusion

A true Muslim is someone who actively follows the Quran word for word and works to transmit the disease to others, while he himself is engaged in horrific acts of mayhem and violence to demonstrate his unconditional obedience to the dictates of the Islamic cult.

None of the numerous contending sects is indeed the Islam Muhammad launched.  That original Islam died with Muhammad; the belief immediately started splintering and kept on splintering, each time claiming to be the true Islam and renouncing and fighting every other splinter.  Yet they still have the Quran, the manual of intolerance and terrorism, in common, which allows and even prescribes violence to please Allah.

Disease is disease, irrespective of strain.  Islam is Islam, irrespective of sect.