Ok, I am not muslim, but I have studied the islamic faith for a few years now. (Personally, I dont believe in any of the religions, just that there is a higher power) but I'll take a stab at these questions.
1. Why are you so quiet.
Fear. 'nuff said. Yes, there are many radical muslims in the world, but there are many peaceful ones as well. Now, say you were in a gang laden neighborhood here in America, and there was a gangwar in your area. One gang is dominant in your neighborhood and you disagree with them. Would you publicly protest their actions? Most likely not, unless you have a death wish.
2. Why are none of the Palestinian terrorists Christian?
Because for the fact Palestine was a dominanty Arab nation, and although there are Chritian Palestinians, they are not as oppressed and shunned by the Isrealis as the Arabs are. The Jews and Arabs have been feuding for mellinia now, and there will be no end. Now they hold the power there, and are taking it out by oppressing the Arabs who had oppressed them in those lands.
Is it really fair that if a Palestinian blows himself up and kills 3 Isrealis. The Isreali Army retaliates with a missle strike on a "Terrorist Outpost" Or what is more commonly known as Refugee camp, and kill well over 40 Men, Women and Children? Is this right to do?
3. Why is only one of the 47 Muslim-majority countries a free country?
The labling of a "Free" country is given to one mainly not run by the religion of the leaders in a sense. Arab nations follow the holy book, the Q'uran, as its supreme law. And abide by that strictly, thus, other nations do not label it as "Free" because the holy laws of the book are far outdated, and very restricting.
4. Why are so many atrocities committed and threatened by Muslims in the name of Islam?
This one constitutes my favorite line to use. "It only takes one madman to corrupt a religion, and Islam was next on the list." Many of the radicals make their claims in the name of Islam, saying that the holy book says to slay the infidels, but, if you actually read the book, you will learn that this is not true at all. The Q'uran is a book of Hospitality. Which is one of the most important pillars of the Islam faith. But over many years, the teachers of Islam have twisted the words of the faith, into a more bitter violent meaning. And teaching someone from the time they are young, to kill the infidels, and that god wills you to do this, what do you expect?
5. Why do countries governed by religious Muslims persecute other religions?
The fact of Saudi Arabia not allowing churches or synagoges, that nation is the seat of the Muslim holy land, with Mecca inside its borders. It is just the same as The Holy See in a sense. You think they would let me build a Mosque within the borders of the Vatican City (Which is a soverign nation to those who didnt know)
The Taliban was a radical group that came to power in an arabic nation, following the teaching that "Infidels are bad and should be killed, and anything of those infidel religions.
The Sudan's islamic community is also radical, in a nation that is in a state of Chaos. Both sides are fighting and killing eachother. The Media is playing on the fact of Muslims killing the Christians to add fuel to the fire. But there have also been slaughters of Muslims by Christian factions.
Now... I hope my attempts were pretty good at these questions, and I again mention, I am not arabic, muslim, or religious in any sense, so I could be faulty on my answers, but I am answering in the sense of the facts I know.