Think of religions like cake.
On the outside it looks so appealing that you just have to have a piece. The frosting and piping and elaborate decorations are the things that particular religion shows off to the world. Beautiful architecture, holidays, ceremonies and messages of love and peace.
Some people window shop before they pick a cake, but most eat their parent's cake during childhood and get used to eating that particular cake and are satisfied with it.
You didn't bake the cake so you aren't going to know what ingredients went into the cake unless you look at the recipe. Some people need to know what they're eating because some things are toxic to them, some people want to know what they're eating so they can choose what goes in their body, some people don't care what the cake is made of.
The recipe for your religion cake is the religions holy text and history. Some people look at the recipe and reject the cake, some people decide to only lick the frosting, and some people shovel the cake in their face anyway.
The health nut who looks at the recipes and concludes All cake is full of seriously bad shit! is the anti-theist. The frosting lickers are your moderates. They want the pretty and the sweet, they deliberately fill up on frosting before they get to the cake so they eat less of it. They don't like all the ingredients so they're selective about the bites they take. The one shoveling it in like Goku at a buffet is your fundamentalist. They know their cake has some hard core shit in it, but its the best and everyone should eat it!
The problem with cake is it has the potential to make you sick. Someone with a peanut/genocide allergy isn't going to dive into that cake. Over eating or excessive amounts of cake over time can have negative health consequences. It could lead to diabetes/ a defective set of morals.