Those are all good arguments against praising Columbus. Especially his insistence that he had found India is a strong argument against saying he discovered America.
The specific argument “but it's not a discovery because it was already inhabited” is a particularly literal-minded child applying their teacher’s prohibitions on plagiarism to the real world.
The specific argument “but it's not a discovery because it was already inhabited” is a particularly literal-minded child applying their teacher’s prohibitions on plagiarism to the real world.