By looking through the ongoing discussion, it was interesting to find a reference to the core-js issue [0] from earlier this year. Its maintainer, with his established position in the npm community, makes use of a similar post-install script to open up a discussion and communicate his situation. This gives him a more direct communication channel to its users without directly helping his situation.
What I assume can be understood as a rent-seeking practice, is how fooreys intention, with the same political power in maintaining a popular package, seems not to be solely to raise awareness to his situation. But instead he's forced a solution to his problem by advertising unrelated 3rd party products. Whereas he interestingly also uses the term experiment, it did already render npm as a space for advertisement.