All these comparisons to satan are patently inaccurate. That's a religion with one God and one bad figure in the form of satan.
It's not the same as a world with multiple religions and hundreds of different monster races; it's a wonder anyone in that setting can keep anything straight in their heads.
No. Like has been told to you several times by several people, Shar is not some unknown deity from a completely different part of the world. Knowing about Shar and what she wants to do with the world is not some esoteric knowledge you only find in forgotten tomes after devoting your life to studying weird religions. It's not something you have to try hard to "keep straight in your head" -- it's something people see in the moon every day. When children ask why the moon comes and goes parents tell them the story of Selune and Shar. You can't weasel your way out of this by going "oh but the world has SO MANY religions" -- even if it does, this is how they believe in Faerun, on the Sword Coast, where we are and the game takes place.
Quite frankly, it's not us who are examples of rigid thinking and not understanding how the world or people works. It's you.
