Pi follows three religions in the novel. He finds value and meaning in Christianity, Hinduism, and Islam.
Pi likes Christianity because of Jesus Christ and his sacrifice. Pi narrates that it was Jesus's "humanity that I found so compelling." Pi found a lot to admire in Christ's selflessness to sacrifice himself. Pi found it illogical but touching, and after thinking about how selfless an act Christ's sacrifice was, Pi was a follower of Christianity.
Pi like Islam because of it very active, and open devotion. He likes the idea of praying 5 times per day, because it is a constant reminder of the faith. He likes the open air mosques, and he likes the emphasis on the brotherhood of Islam.
Hinduism appealed to Pi because it basically unifies god(s) with all of creation. Related to Islam's open air emphasis, Hinduism places a spiritual component on many tactile and earthly items. Pi also likes the idea of Karma. To him it shows an aware universe. It means that actions matter.
Martel might be trying to say that following a specific religion is unnecessary. He might be trying to say that all religions tend to lead to the same result. A love for your fellow man, a love for the creation, and a devoted love to a god(s). To Pi, and possibly Martel, each religion is simply a different expression of the same core belief. Each religion has its own story and traditions, but they each provide the same function -- to give people comfort and guidance. Pi simply was open about the fact that he was willing to take from each religion what gave him the most spiritual comfort.