I think it goes without saying that they believe what they want and other will do the same. I doubt that would have been the theme in the crusades, most realigns are cults anyway. If you think otherwise, your probably into it way too much. You can't think your right over another person, with no proof.
Religious sects are most definitely biased in there views. All the sects that are out there are scary in what they believe in and they usually have a tendency to show their bias. They are brainwashed by their leader and then the bias really comes out and shows itself. This needs to stop.
Each religious sect has its own dogma and its own bias. Religious sects are biased towards their own belief systems and people that follow those tenets. In terms of Christianity, sects try to get new members with recruitment. That increase in membership means more money. In that respect, bias towards one idea or another leads to an increase or decrease of money.
There is a profound happiness that occurs in some sects of religion. This happiness leads to a community of people who think and care for each other, to try and improve each others lives. When they are a truly kind community, they can be accepting of outsiders, and give their comfort in the name of hospitality and kindness.
I believe the majority of religious sects are nothing more then a fraction of the members of a church who have decided to go about their own way of practicing the religion, I don't think that they are biased or hold an opinion that their way of practicing is better then the other religions.