I fear it's because religion is man's attempt to reach God, and when he feels he has succeeded, he cannot abide anyone else's claim to have done the same.
A dislike of death is no proof of the want of religion. The instincts of nature shrink from it, for no creature can like its own dissolution. But though death is not desired, the result of it may be, for dying to the Christian is the way to life eternal.
In morals what begins in fear usually ends in wickedness; in religion what begins in fear usually ends in fanaticism. Fear, either as a principle or a motive, is the beginning of all evil.
If there is any fixed star in our constitutional constellation, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion, or force citizens to confess by word or act.
I think Muslims have become the new Negroes in America. They are being mistreated at airports, by the Immigration - everywhere. Islam is a religion of peace. They are wrong.