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.
build/Release
# Dependency directory
-# Commenting this out is preferred by some people, see
+# Deployed apps should consider commenting this line out:
# https://www.npmjs.org/doc/misc/npm-faq.html#should-i-check-my-node_modules-folder-into-git-
node_modules