Many have made this point before me. But adherence to irrational supernatural beliefs can be deadly. Like when mobs go after "witches." Not black-hat-and-broomstick witches like you'd see at Halloween or in a Harry Potter movie, but animistic witches, practicing "sympathetic magic" like voodoo dolls or placing hexes on their enemies. Belief in such witchcraft is a powerful facet of the religious beliefs of people living in various parts of the world, like the Kenyans described in the linked story.
It seems obvious to us Westerners that the victims in the linked story were not witches, because there are no such things as witches. Witches, witchcraft, and other kinds of magic are facets of fairy tales, fables, and folklore, not the world of reality. But to pooh-pooh the belief in these African witches is to denigrate someone's religious beliefs as "mere superstition." Were I to denigrate the religious beliefs of, say, a Catholic who thinks that torture combined with prayer can exorcise demonic possession as the credulous, hysterical, and harmful exercise of "mere superstition", I would run a serious risk of being condemned as being prejudiced against Christians.
I'm not sure how to be respectful of the beliefs of other people -- something I want to do because it seems normatively good and in conformance with the high ideal of tolerance -- while still condemning something like this. And I can't help but condemn the mob murder of people who probably did nothing more than participate in a meaningless but otherwise harmless ritual. At what point do we defer to "religious belief" and at what point do we condemn "mere superstition"?
Remember, the folly of a large number of people is still folly -- Christians, for instance, must surely think that the one billion or more Hindus on the planet are subscribing to a false religion, and the fact that a billion people share that set of beliefs in no way redeems the validity (or lack thereof) of Hinduism. And Hindus no doubt feel the same way about Christians. At least one of those two sets of beliefs must be wrong; Hinduism is logically incompatible with Christianity (even though Hindus and Christians can certainly be friends and may share a great many moral values).
So it can't be "when lots of people subscribe to the belief, it's worthy of respect." Lots of people once believed the sun revolved around the earth, not the other way around. They came to that belief based upon a reading of their religious texts. But they were wrong. The Earth orbits the sun and spins on its axis; we now know this to be objectively true. The "inerrant" holy books, or at least the way doctrine told people to interpret those texts, were simply and objectively wrong. People died because of those doctrines. People like the "witches" in Kenya are being killed today because of obviously incorrect religious beliefs. Debatably, the Christianized west is at war with the Muslim middle-east because of fundamental and long-standing disputes about religion.
I think Richard Dawkins is right about this: religion does not make the world a peaceful place. Religion causes violence.
It's easy to want to be respectful of people whose beliefs are different than your own. It's more difficult in practice to actually be tolerant. And by the time someone else's weird belief in the supernatural moves them to violence, it's time to drop tolerance and start condemnation.