I think everybody can have the religion that they want and it is good to respect what everybody believes. So for example in our family we are Buddhist or at least MOST in our family. But i respect it if somebody is for example Christian or Muslim or Hindu person. So there is not only one religion but as many as people believe and what is really important for them.
Jesus Christ taught us to love even our enemies. Therefore, we must have respect for other religions and for non-believers. The era of the crusades is fortunately over.