It is good to normalise that because that is true. Children are not allowed access to lots of things, and that is a good thing.

Yes, "content that isn't gender or sex normative" should be included. Children should not be exposed to sexual subcultures or encouraged to experiment with gender non-conformity. They are not ready to handle that.

They may be ready that's why they are looking but you might not be.

The real question is, what is it that you're so afraid of with gender/sexuality that you think it makes sense to show some expressions of it but not others? Sexual norms change regardless of what is officially considered normative and regardless of what is repressed, so you must know you're fighting a losing battle. So who or what is it exactly that you're fighting for? I think it has more to do with yourself than with children.

What is it about “sexual subcultures” that are inherently dangerous as opposed to the main culture that is inherently safe.

Is a book character being gay unsafe for kids in a way that the same character being straight is not?