What is a fundamentalist group? It’s a group which practices its written doctrines. In the case of alarming Islam, it’s carrying-out the instructions of Muhammed to subdue the world for Islam by force when necessary. For fundementalist Judaism, it would be killing adulterors and other violators of the old testament law, but for fundamentalist Christians, it’s preaching by the Word the Good News of Jesus Christ to the world.
The jewish law in the Old Testament was to show that God hates sin, severe punishment for it meted out by the people of Israel on violators of that law, that nation ‘though all the ‘while “the apple of God’s eye,” because Elohim had chosen them to reveal to the world some of the nature of his ways and desires. Yet with the incarnation, death, and resurrection of Jesus Christ the Messiah, the animal sacrifices required in the Old Testament were no longer needed, because Jesus part of Elohim is the Lamb of God who atones for the sins of all who believe on him.
So what real harm or cruelty manifests by the preaching to the world of new testament Christianity, compared particularly to fundamentalist Judaism and Islam? Fundamentalism in the case of true evangelical Christianity is not to fear at all, unless the message of the Good News just vexes your soul in its fallen state, yet far better that than having your hand cut-off for stealing a can of juice, right? Fundamentalism is scary only when the fundamentals are scary, only Jesus Christ holds out his hand of forgiveness to you.