Why do we fail to live up to our own personal standards? Is it a surprise that a large group of people fails to do what even the best person fails to do? You get all kinds of people in a religious group: the legalists, the people who think they believe but actually have a higher priority, the immature people, and the mature self-givers. Legalism has inherent contradictions that can easily end up treating people poorly. The people who have a higher priority that than the values of the group are likely to act outside the values of the group, which is especially noticeable if they are in leadership. The immature people want to do the right thing, but fear, emotional issues, etc. exert a stronger pull.

I don't think the purpose of religion is to "align yourself to the highest aspirations", though, but rather to make sense of our place in the world and how to rightly live within it. They have rather different views of this, of course. Traditional Christianity says our place in the world is as children of God who are intended to be the image of God in the world and shepherd it with God's self-giving love. (Getting saved to go to heaven is a relatively new simplification.) Buddhism, in contrast, observes that all composed things are impermanent, so nothing is actually real and forming attachments to things causes pain. The ethics flow out of the views of our relationship within/to the world.