I don't see the issue.
What I find ironic, is how much HN despises anybody who tries to make money from their work. There's a bizarre ideal here of the selfless internet "Mother Theresa," who exclusively works on open source projects and only shares things with the world out of passion.
You could spend 3 years compiling research on an extremely valuable topic and publish it for free...but if you put a newsletter sign-up form on the page, somebody here will complain about it.
Strange, considering HN is hosted by an entrepreneurship incubator.