I found the article to be a little more balanced than that. But, basically once I saw that spine.js is written in coffeescript I wasn't really interested.
It's not just the source. A lot of the documentation is only available with CS examples (even though they provide a switcher at the top of the page), which also means the ecosystem (in terms of people writing blogposts about Spine) is divided in Javascript and Coffeescript examples.
