Sites are free to overuse 'rel=nofollow', and search engines are free to selectively ignore it (for either link-discovery or ranking purposes).
The strongest point I see made by this author is about SO's hypocrisy: SO requires attribution to be with a link, and specify that link must not have 'rel=nofollow'. Yet their content relies heavily on references to elsewhere which are all 'rel=nofollow'ed.
A sense of fair play in attribution, and spirit of mutual assistance between reliable authorities, would suggest allowing at least some well-vetted outlinks to be unencumbered.
If you republish this content, we require that you: [...]
Hyperlink directly to the original question on the source site [...]
This is about the spirit of fair attribution. Attribution to the website, and more importantly, to the individuals who so generously contributed their time to create that content in the first place!
Anyway, I hope that clears up any confusion — feel free to remix and reuse to your heart’s content, as long as a good faith effort is made to attribute the content!
If the link to stackexchange was user-generated content I seriously doubt they would actually expect it to have nofollow.
The outgoing links to any site from the stackexchange blog do not have nofollow. Any content that they are explicitly curating does not have nofollow, any user content does. I think that is a reasonably consistent policy.