Freedom, ownership and copyright: why does Kant reject the concept of intellectual property?

In 1785 Immanuel Kant wrote a short essay, Von der Unrechtmäßigkeit des Büchernachdrucks, which is sometimes translated as Of the injustice of counterfeiting books; later, he repeated almost the same thesis in the Rechtslehre, § 31, II, within Die Metaphysik der Sitten (1797). As most scholars, in the field of humanities, take intellectual  property for granted, the representation of Kant like an intellectual property forerunner is still a commonplace [...]