I like to think of religion (or most religions) as early attempts at psychology and science, and they should be preserved, so long as they do not interfere with the evolution of Mankind and are not being forced upon people.
It is just really disgusting and even disturbing when people literally believe what their religion tells them (which has often been diluted through priests, etc.) and base their whole lives around it.
It is preposterous to assume that millions and millions of people happen to have within them exactly the same opinions about various different subjects. The brainwashing is too obvious and it is scary. I was baptized and going to church and learning the Bible before I understood what any of what I was being told meant, and that is simply wrong. Fortunately my parents didn't care much about religion, so when they moved out of my grandmother's house I stopped going.
Another thing I find strange is people whose countries have a heathen background but were Christianized, and they now seem to be glad and very religious. For instance, the same people who would criticize Christians for having invaded his land and destroyed much of it in the process and generally caused chaos to an otherwise peaceful place simply because they found themselves superior, will at the very same time praise Haruhi and be the most devout person in the world. It just seems hypocritical that people don't understand, especially after learning some history, that they have been conditioned to believe what they believe.
This post became way too long.