Regarding the art depicted, I'm asking how is this allowed seeing that they have replicated the Tintin drawings for an article?
You’re really only going to get an anwer to this by asking the paper or Moulinsart; otherwise it will just be speculation.
There’s possibly some lee-way under the accepted use of parody in press illustrations to begin with; the use of characters, likenesses, logos, trademarks etc. to make an editorial point is a plank of freedom of the press. The extent to which this goes is open to interpretation, and papers will often go further than might be otherwise allowed; however, the party upon whose rights they have trampled may be willing to accept it if the intention is bneficial to them, or there is already some reciprocity in place (such as getting a positive, multi-page feature which has been published internationally out of it).
You also have to bear in mind that the stipulation about no new Tintin after his death made by Hergé was by way of a request; his widow (in whom the rights to Tintin rest) has the legal right to grant permission as she sees fit. She also has oversight of the Studios, the charitable foundation which exists to promote the works of Hergé – if it is beneficial to the activities of the Studios, and not derogatory of the legacy, there’s every chance that they’d agree to such a promotion.