The seeking of commerce is clearly not equivalent to its attainment so Kant does not here speak of a right to commerce but only of a right to be able to attain it. Niesen understands this as "a communicative right", that is, a right to make "communicative offers". Somewhat oddly and partly by associating this with statements Kant makes at the conclusion of the Doctrine of Virtue concerning social intercourse (Ak. 6: 473) this communicative right is presented by Niesen in terms of a general right to free speech on Kant's part. More persuasive evidence for a connection between the statement in Perpetual Peace and a view of free speech rights are the references Niesen points to elsewhere in Kant's works. For example, in the introduction to the Doctrine of Right, in the context of discussing the "one innate right" to freedom Kant derives from it some authorizations which, he says, "are not really distinct from it" (Ak. 6: 237). Included amongst these are "such things as merely communicating his thoughts to them" (Ak. 6: 238).
As part of his concluding remarks concerning the relation of theory and practice in the right of a state Kant also arrives at the key importance of making publicly known one's opinions. Here Kant explicitly states that "freedom of the pen" is the sole means by which the people's right can be expressed in relation to a sovereign, an argument used there in response to Hobbes (Ak. 8: 304). Niesen lists these points alongside each other as part of a general argument in Kant for freedom of expression.
Without directly here attempting to engage Niesen's specific argument for a general argument for freedom of expression I did think it worth returning to the relationship between commerce and communication and what this might tell us about hospitality. If a right to seek commerce is to be understood in Niesen's sense, as a special kind of communicative right, then it follows that restriction on commerce is a form of restriction of communication. Despite this, it remains true that in the discussion of the third definitive article of perpetual peace that Kant remarks approvingly on the restrictions of commercial practice imposed on the Western powers by Japan and China. The reason for this is due to the colonialist policies of these powers, policies that Kant here clearly condemns.
The consideration of Kant's attitude towards these policies of China and Japan leads Niesen to argue for a distinction between commercial speech strictly speaking which covers "messages that are economic in intent" from a general commitment to free speech. So, despite the fact that Niesen initially interprets the reference to commerce in the treatment of the third definitive article as a communicative right he is nonetheless driven by the consideration of the examples of China and Japan to understand hospitality in such a way that restriction of commerce can be compatible with it even though commerce is the first referent Kant makes to help us understand hospitality.
Niesen is guided by the understanding that Kant is not committed in principle to unrestricted free trade and the approval voiced of the restrictive policies of Japan and China do make this clear. However it remains true on Niesen's account that we need to connect the treatment of commerce as a form of communication that is apparently open to restriction to two other elements of Kant's account. Firstly, to the provisional possession of the property of the earth (which should be, but is not by Niesen, connected to the state of nature between states) and to the injustice of colonialist adventures. If commerce as a communicative act is restricted by the latter it is nonetheless in some sense commended by the former. Further, someone who is washed up on the shores of a foreign place and not able to engage there in commerce due to restriction faces the prospect of death, the very prospect that should be ruled out by the right of hospitality. Niesen's restrictive understanding of commercial speech seems to raise serious problems for the consistency of Kant's view.
Without wishing to articulate a reading of hospitality that would commit Kant to a universal right of free trade it remains problematic in principle to endorse the restriction of trade Kant apparently allows when it is in conflict with a basic understanding of the right to hospitality. So a reading of the view of the trade policies of China and Japan that is not simply based, as Niesen's is, on a restrictive view of commercial speech, seems required.