Because they've never really read the Koran. Invest the time, and it will open your eyes, you'll then know how it has been perverted by so many, all to support their own ideas of hate and murderer. Remember, even in the Bible we find the quote an eye for an eye! Yet gods commandments state thou shall not kill! A conundrum, yes?
On paper all religions promote peace and harmony, in practice very few actually succeed at it. All the branches of the Abrahamic religions have their fundamentalists, these extremists are unwilling to compromise in order to find common ground with one another.
Jihad is practiced by extremists and fanatics. If you read the Quran youll find it reads much like the Bible, promoting peace over violence. Extremists want to hurt others and they take one or two verses out of context in order to do so. The Quran and Bible have a great deal in common. We Christians dont have a word for it like Jihad but Gods people certainly often made war against Gods enemies, tho God demanded peace after Christ came. Most of the crazy muslims are poor and hate America for being wealthier and stronger. They are easily convinced by richer better educated men to hate even harder. Notice the ones who kill themselves are the poor men and fanatical idealist students not the rich, well educated older men. In general Islam is just as peaceful as Christianity.
FYI: on Christian radio/am listening to Erwin Lutzer( has new book out:The Coss in the Shadow of the Cresent) Is discussing parts of it in his daily broadcast. 1. Muslims will not pray within the site of a cross( thus the demand in this country to distroy and rid any cross ! 2. Any church that becomes vacant , they will turn it into a mosque . This is considered a victory for Islam! Also at sites of any victory( twin towers 9/11.)
Unfortunately, not all promote peace. It's sad. Even in war you'll oftentimes see priests blessing soldiers, when the Bible clearly indicates that we should love our brothers. God did say that his people would be identified by the following traits:
1. base their teachings on the Bible (2 Timothy 3:16,17) 2. worship only Jehovah and make his name known (Matthew 4:10; Psalm 83:18) 3. show genuine love for one another (John 13:35) 4. accept Jesus as God’s means of salvation (Acts 4:12; John 3:36) 5. are no part of the world (John 18:36) 6. preach God’s Kingdom as man’s only hope (Matthew 24:14; Daniel 2:44)