What Bud said. Islam is a very basic religion, and the complexity of Christianity puts us at a disadvantage in areas where missionaries of both religions are proselytizing.
If you’re some pagan, looking for a better answer, and a Muslim comes along, saying, "My God is the only God, and you must do the following:
- Profess your faith to him
- Pray five times a day
- Abstain during Ramadan
- Give to the poor
- Journey to Mecca once in your life
That’s all there is to it, although we’ve got plenty of guidelines to help you follow these five pillars"
Then along comes a Christian, saying "My God is the only God. Here are 10 Commandments you must follow - they’re pretty basic. Oh, and by the way, my God had a son. But the son is God, too, and the same God, but distinct. Did I mention there’s also a spirit flying around who is God, and the same God, but also distinct? And after God made us, he decided he needed to save us, since we are prone to sin - no, he didn’t exactly make us that way, but… So to save us from sin, he decided the best way would be to kill his son - remember, the one who is also God? -
By this time, the pagan’s head is swimming, and he high-tails it back to the Muslim.
So there is a very real difficulty in explaining the truth to non-Christians, without it seeming confusing and bizarre. In Islam, on the other hand, you can save the more whacked-out aspects of the faith for after the person is converted and pretty well set in their path.