The difference is that the catechism of the catholic church teaches love and respect for all people. You have to remember that extremists make all people look bad. Think of Islam. Anyway, you have to take things in context. Look at the fundamental teachings of christ. Read the New Testament, it will be good for you. All religions follow those fundamental teachings, and the only reason for the crusades, and all of those other things you mentioned, was that some extremist's power went to his head and he decided to start making rules. Also bear in mind that if Hitler had died in 1938, he would have been hailed as a hero. (He was Time Magazine's man of hte year in 1938.)