The difference between fanaticism and true religion.
Fanaticism is an unhealthy set of principles that takes the letter of the law too literally and avoids compassion or feeling towards self or others. It is found in all faiths and ideologies. It is part of the human narrative.
On the other hand, true religion is one who lives by the higher law of love and commitment to truth. A condition that takes much more effort, patience and sacrifice to achieve than simply following a legal code.
There are good Christians and bad Christians, same with socialists, capitalists, Jews, and also Muslims. History shows that even non-religious systems such as Communism, and the attempted establishment of Western Democratic countries in the Middle East have run into the same problems of fanaticism. The ancient texts and modern history weaves the account that wherever humanity exists, greatness is found, but also the element of corruption and inhumanity always runs in parallel.