There definitely is a war, but not just between Christianity and Islam, but between almost all religions.

Palestine (Jews v. Muslims),
the Balkans (Orthodox Serbians v. Catholic Croatians; Orthodox Serbians v. Bosnian and Albanian Muslims),
Northern Ireland (Protestants v. Catholic),
Kashmir (muslims v. Hindus),
Sudan (Muslims v. Christians and Animists),
Nigeria (Muslims v. Christians), Ethiopia and Eritrea (Muslims v. Christians),
Sri Lanka (Sinhalese Buddhist v. Tamil Hindus),
Indonesia (Muslims v. Timorese Christians),
and the Caucasus (Orthodox Russian v. Chechen Muslim; Muslim Azerbaijanis v. Catholic and Orthodox Armenians)

In these places religion has been the explicit cause of literally millions of deaths in the last 10 years.

So much for religious tolerance and peace....

Now whay exactly is it that it's so taboo to point to someone, or a group of people and say that their religion is causing the deaths of many people? Is it not the truth?

You will reply and say that these people are not true believers, or that they misinterpret their own religion... When a given religion claims infallibility, and claims to be the word of the one true god, it is by the same token completely incompatible with other religions, there's no way around it.