The saint and the sinner are still people; nothing prevents the roles from flipping.
In religion, two sides that are called "light" and "dark" are usually mistranslated "good" and "evil" and in doing this, create discord and cause destruction throughout the world.
The majority if not all of the religious constructions of man have similar veins running through them.
Instead of worrying about the differences, try to see the similarities. Perhaps from the similarities you can distill the truth.
Friedrich Nietszche signaled the end of the religious thinking of mankind and foresaw that this would be the downfall of mankind.
However, mankind continues to express religious thinking divorced from actual deities through the "progressive" modes of science/technology.
Religious thinking, in any circumstance, will not solve the problems of mankind.