In the case of my family, it was understood as a matter of biological science and nothing more.

[Never mind the particulars, which Alucard knows more than ever to avoid.]

The art in there was made by someone who truly believed the creatures within to be real, but assigned no moral judgement to them. They were simply other animals to study.

[Hector's notebooks had long outlived the man. Alucard retained them out of a sense of respect to his father.]