God has created man for a reason. HE gave man the brain to think and gave him the will to choose. GOD Almighty did not force man even to believe in HIM. Angels for example do not have a choice, they were created and believing in GOD was not optional, they had to believe. This is not the case with us humans, we have a choice. You can choose to believe or not and your choice will not make GOD avenge HIMSELF by making you for example poor or anything (as long as you work of course).
GOD wants us to CHOOSE to love HIM. In the verse (10:99) God says: "And had your Lord willed, those on earth would have believed – all of them entirely. Then, [O Muhammad], would you compel the people in order that they become believers?". So the idea of obligatory faith is totally refused in Islam since it defies the very core of why we were created in the first place. In another verse God says: " There shall be no compulsion in [acceptance of] the religion. The right course has become clear from the wrong. So whoever disbelieves in taghut and believes in Allah has grasped the most trustworthy handhold with no break in it. And Allah is Hearing and Knowing." (2:256) .
If God wanted us to believe then HE would have created us like the angels, involuntary. But HE gave us the choice and armed us with the brain to guide our footsteps to HIM. In lots of verses GOD encourages people to use their minds.
In the Holy Quran words like "are signs for a people who use reason.", "so will they not understand?", " Thus does Allah make clear to you [His] verses that you might give thought." In fact "mind" or its derivatives were mentioned 49 times in the Holy Quran (a small tip: it is the same number of occurrences of the word "light" in the Holy Quran)
In other verses God tells us to ask HIM to give us knowledge like in the verse (20:114) that says: "and say, 'My Lord, increase me in knowledge.' " The first verse revealed from the Holy Quran says : "Read [O Muhammad!] in the name of your Lord who created." (96:1). In other verses God clarifies to us that the knowledgeable have higher ranks like in the verse (39:9) that says: "Say, 'Are those who know equal to those who do not know?' Only they will remember [who are] people of understanding."
In other verses GOD blames those who do not think by saying: "Indeed, the worst of living creatures in the sight of Allah are the deaf and dumb who do not use reason." (8:22) Prophet Mohummed, peace and blessings be upon him, said: "If man dies, his righteous deeds will be ended and so is the reward but this righteous deeds can be incessant if he left behind continuously-rewarded (Sadka) alms or useful science or a righteous son who would invokes Allah's mercy on him." ( Narrated by Moslem ). In another hadith our noble Prophet, peace and blessings be upon him, also said: "The preference of scientist over the worshipper is equal to my preference of mine over the least among you" (Al-Termithi)
Even in the matters of faith itself GOD encouraged man to think and question. The famous story when Prophet Abraham asked GOD to show him how HE could raise the dead. The Holy Quran narrates the story as follows: "And [mention] when Abraham said, "My Lord, show me how You give life to the dead." [Allah] said, "Have you not believed?" He said, "Yes, but [I ask] only that my heart may be satisfied." [Allah] said, "Take four birds and commit them to yourself. Then [after slaughtering them] put on each hill a portion of them; then call them – they will come [flying] to you in haste. And know that Allah is Exalted in Might and Wise." (2:260)
So Islam is not about obligatory faith, you believe or go to hell, no its about logical, unbiased thinking that leads you to believing. A famous respected, Muslim, Egyptian writer Dr. Mustafa Mahmoud wrote two best sellers called "My Journey from Doubt to Faith" and "A dialogue with my friend the atheist" (I strongly recommend reading these ).
This man refused to "inherit" a religion so he decided to free himself of any bounds to any religion then to look for himself and search till he CHOOSES a religion to follow. The book are really great. What Dr. Mustafa did IS NOT a sin, search for GOD in your heart and read that is what GOD wants from every human. Search and think and analyze till you find your comfort, that is Islam.
Islam does not want millions to "inherit" Islam or take it as part of their ID, Islam wants a Muslim whose heart, soul and mind are convinced and found comfort in Islam. This Muslim CAN NEVER be a terrorist. He can and will make mistakes because he is human but he can never kill any living soul in cold blood.