It's not the opinion of "some people", it's a conditional circumstance.
Even proponents of checking node_modules into Git agree that you
shouldn't do it when you're writing a module to be included as a
dependency on npmjs.org: the advantage of checking node_modules
into Git is only for fully-packaged apps, which is why the original
comment was what it was.
These aren't really common patterns in the Node world, and if a Node project includes one of these types as files, they're as likely to want to include them in the project as not (`*.csv` is as likely to be a data source as `*.json`).
This re-covers the http://nodejs.org/api/addons.html case for which the "build" directory was added in 00686415c4, but doesn't break cross-environment projects that use the build directory for including concatenated/minified source. Mazel tov!
The "build" directory is lost in this refactor, as many JS projects
do wish to include a minified/concatenated version of their source
in the "build" folder in source control.
Stuart P. Bentley