Exactly. The existence of Magic completely throws a wrench in any definition of species based on real-life genetics. We don’t even know for certain that there is such thing as genes in D&D, so there’s no sense trying to apply a geneticist understanding of species there. But, species are a closer analogue for the relationship (or, lack of relationship) between humans and orcs than race, based on how those words are typically used.But according to the lore orcs are also magically fertile. Which means they can be a separate species as well.