No one knows why but it’s often said(with anecdatas) that >50% of creators for these content are biological female.

So girls draw sexualized girls, some men do as well. Some says the high composition of female artists comes from the fact that moe arts are extension of Shoujo Manga market where predominantly female characters are portrayed by predominantly female artists for predominantly younger female audiences.

Whatever the actual reason might be, it’s probably more complicated than “person with polar opposite sexuality of the subject consume porn”.