It's honestly just following logic in a mathematical way. Check out the "all" quantifier.
The phrase "all unicorns have a horn" is true even if there are 0 unicorns. This is something that apparently was a problem back in the middle ages when there was only propositional logic and no predicate logic. It was thought that there has to be a unicorn if we want to say they all have horns.
So if you have a problem with these types of statements, you're using zeroth-order logic and need to upgrade your logic to first-order logic.