Meh, pretty good claim of fair use. They are just picking a smaller file that unlikely to disappear or move. The fact the file is downloaded and then deleted via a script isn't a substitute for actually viewing the file and has zero commercial impact.

And the take down could have been targeted against the particular files they found problematic rather than the whole project.

And the whole thing is ceded to the public domain. Anyone can remove the examples and unit test, call the code webvid-dl and be golden.