I think the issue is faith in the Messiah. Everything flows from believing what he said.
So do I, and it's what I've lived my whole life. But there are those who hold Catholicism as their private fiefdom, and have no problem viciously attacking anyone who interprets Catholic teachings differently from their beliefs. I've been attacked, for example, by a maniac for three days now on another thread who has decided that my understanding of Catholicism is deficient. He's written over a hundred pages of seething invective against me and will not stop - nor will the Religion Mod stop him. And why? Because they obviously agree with each other. So while what you say is true, it's simplicity does not address the dehumanization and hatred people allow themselves to indulge in over religion - even one literally based on the command "love one another."