Buddhists in Thailand, Jews in Israel, Christians in Indonesia, Hindus in India ... Why is the Islam at war with any great world religion when none of these religions is at war?
A part of reason is that the Koran is specific about the inferiority of other faiths (see 48:28) and the hate which Allah has for their people.
Although religious Muslims are usually annoyed when someone "offends" their religion, here is what the Koran says about Jews and Christians:
And the Jews say: 'Uzair (Ezra) is the son of Allah, and the Christians say: Messiah is the son of Allah. That is a saying from their mouths. They imitate the saying of the disbelievers of old. Allah's Curse be on them, how they are deluded away from the truth! (9:30 see also Bukhari 8:427; One of the last things that Muhammad said on his deathbed: "May Allah curse the Jews and Christians.")
The Koran refers specifically to Christians, Jews, polytheists (Hindus) and atheists:
Christians are unbelievers (98:5-6) and blasphemers (5:17, 5:73) who have invented a lie about Allah (10:68-69) by sharing Allah's (i.e. trinity) partners call. The worst sin is the invention of a lie about Allah (7:37, 29:68) and for this reason the Christians are condemned to hell (10:70). Although an early-Medinan verse seems to say that just Christians are coming to heaven, this is abolished by later verses that make it very clear that Christians must cease to be Christian (i.e. reject the trinity) or eternal torments for their faith (5:72-73).
Jews are also cursed by Allah in one of the last "pronouncements" of Muhammad (5:13). The Koran assures Muslims that Jews are evil (4:160-162) - so evil that they somehow managed to do the impossible (18:27) and to change the word of Allah (2:75). Jews are "liar" and "devour the forbidden" (5:42). They are the worst enemies of Muslims (5:82)
The Koran assures to the faithful that Jews and Christians have "sick hearts" (5:52). Allah even refers to the position of enmity to them (5:14). Only Jews and Christians who submit to Islamic rule and pay Jizya are protected in this world (9:29 & Ibn Ishaq 956).
Hindus are polytheists. Although Muhammad did not knew Hindus (and apparently Allah did not), the Koran created the foundation for the 1000-year ethnic cleansing action against the Hindu people, which estimated an estimated ten million innocent lives. In Islam, the polytheists are worse than all other religions. Those who connect idols (11:14) with Allah also invent lies (29:17) and will burn in hell. Even believing in other divine units together with Allah is an unpardonable crime (4:48, 40:12).
Atheists believe in no God, which is worse than believing in the wrong (Muhammad and his successors had killed atheists - Bukhari 84:57). But the question of the existence of Allah is a proof of disbelief (25:21). Muhammad answered only questions by telling the requesting party that they would go to hell if they did not believe in him (36:49-64). The Koran discourages Muslims from the intellectual investigation (5:101-102).
Every Muslim who gives up his religion is a "perverted transgressor" (3:82). Pervert is also everyone who denies Allah (40:63) or does not believe to Mohammad (2:99). Conscience does not exist in Islam. Muhammad clearly prescribed the death penalty (Bukhari 52:260).
While the contemporary advocates of the Islam often speak about "dialogue" they do not mean the real meaning of the word. They understand the unilateral arrangement in which they are talking about the Islam, while others are listening. Among other things, the Koran talks about jihad:
So obey not the disbelievers, but strive against them (by preaching) with the utmost endeavour, with it (the Qur'an). (25:52)
What would be the point when you hear something that a non-Muslim has to say ... or even talk to? Allah has already sealed their hearts and condemned them to hell:
Verily, those who disbelieve, it is the same to them whether you (O Muhammad Peace be upon him) warn them or do not warn them, they will not believe. (2:6)
Allah has set a seal on their hearts and on their hearings, (i.e. they are closed from accepting Allah's Guidance), and on their eyes there is a covering. Theirs will be a great torment. (2:7)
For those who ask why Allah has created even unbelievers when their ultimate goal is hell, Muhammad said that the purpose of some (at least Jews and Christians) is to take the place of the Muslims so that they do not suffer in hell (Sahih Muslim 6666).