The question of "If Islam were the religion of terrorists, then why aren’t most Muslims terrorists?" can easily be turned around.
If Islam is a religion of peace, then why is it the only one that consistently produces religiously-motivated terrorist attacks each and every day of the year? Why are thousands of people willing and able to cut off an innocent person’s head or fly a plane into a building while screaming praises to Allah? Where’s the outrage among other Muslims when this happens… and why do they get more worked up over cartoons and hijabs?
Rather than trying to answer a question with a question, however, let's just say that the reason why most Muslims don't kill is that (regardless of what Islam may or may not teach) it's wrong to kill over religion.
Consider that many Muslims would not even think of amputating a thief's hand. Does this mean that it is against Islam to do so? Of course not! In fact, this mandate is clearly found in one of the last verses in the Qur'an (5:38) and in the example of Muhammad according to the Hadith (Bukhari 81:792).
Muslims may believe whatever they want to about what Islam says or doesn't say, but it doesn't change what Islam says about itself. As an ideology, it exists independently of anyone's opinion. As such, it may be studied objectively and apart from how anyone else practices or chooses to interprets it.
The Qur'an plainly teaches that it is not only proper to kill in the name of Allah in certain circumstances, but that it is actually a requirement. Muslims who don't believe in killing over religion may be that way out of ignorance or because they are more loyal to the moral law written in their hearts than they are to the details of Muhammad’s religion. Those who put Islam first or know Islam best know otherwise.
In fact, few Muslims have ever read the Qur'an to any extent, much less pursued an honest investigation of the actual words and deeds of Muhammad, which were more in line with hedonism, deception, power and violence than with moral restraint. The harsh rules that Muslim countries impose on free speech to protect Islam from critique also prevent it from being fully understood. In the West, many Muslims, devout or otherwise, simply prefer to believe that Islam is aligned with the Judeo-Christian principles of peace and tolerance, even if it means filtering evidence to the contrary.
It is no coincidence, however, that the purists who take Islam too heart are far more likely to become terrorists than humanitarians. Those most prone to abandoning themselves to Muhammad's message without moral preconception are always the more dangerous and supremacist-minded. They may be called ‘extremists’ or ‘fundamentalists,’ but, at the end of the day, they are also dedicated to the Qur’an and following the path of Jihad as mandated by Muhammad.
It is unfortunate that you also seem to be making false presumptions and then asking for explanations. mr420 gave some reports from reputed sources that shows that overwhelming number of terrorist incidents, smaller in proportion to their population are done by non-Muslims. Perception is not reality.
Your loaded questions again are premised on the assumption that they are true. For examples, Muslims don't show outrage against terrorist attacks. Or that ALL Muslims jumped up and down when cartoons were published. Or the first one I have heard, "thousands" of muslims cut of innocent people's head and fly planes into buildings.
This is like asking European Christians after WWII that why is that only European Christians consistently produce mass murderers whether they be in wars or wiping out native populations in the new worlds or enslaving Africans? The question itself is based on a wrong premise.
Again, you have probably read a hate-muslim blog on how "evil" Islam and the Quran is and have concluded that certainly anyone who steals gets his hand chopped off.
Did you even read the next verse 5:39?
“(But) Whoever repents after his wrongdoing and makes amends, then verily God will accept his repentance and verily God is the Forgiving, the Merciful.” (Quran 5:39)
If you ask an Islamic scholar on the legalese behind this, you will be told that petty crimes donot come under this. For eg: a poor man stealing food e.t.c. Also "make amends" and "repentance" implies that if the thief returns the property or makes good the loss in some other way and promises not to do it again, the punishment will be waived as well.
Compare this for example the punishment of theft in the Torah or Old testament where if a gentile steals from a jew, the punishment is death.
Infact, if you talk about violence, there are some pretty violent chapters in the torah and the bible. But we are not in a contest here.
Of course, those Muslims who choose to kill innocent people or fly planes into buildings don't think follow some logical thought process of "cutting hands of a thief" to "lets kill some infidels". This does not have anything to do with the terrorism issue. Its a prime example of obfuscation.
And of course you end of again with presumptions as facts. Please remember, perception is not reality. Most Muslims do get taught the very basics and fundamentals of their religion. And no, they are not required to kill people just for the heck of it. What next, Muslims drink baby blood but they just try to hide it using some "taqiya" magic? Another presumptuous invention about how deceptive the "wily" Muslims are.
The people who actually do commit terrorists acts are those who never had a religiously devout life in the first place. Most of them don't have any background in Islamic theology either. The 9/11 hijackers went out clubbing and drinking and most of their life they were hardly devout. OBL was a businessman not an Islamic scholar. Similarly Zawahiri is a medical doctor. These people suddenly find "religion" and use it as a political cause and tool. Their language may be couched in religious terms, but their aim is clearly political. The same extremism ideologies that other religious extremists be they Christian, Jewish, or even Atheists/Communists have and in their extremism are willing to kill innocent people.
What you need my friend is a visit to your local mosque and ask them some questions, maybe attend one of the sermons and see for yourself and you will realize that Muslims are just people like "Us".