Oh, I don't know that they made the wrong decision - I have every expectation that they thought about this as well and decided it was too likely they did not have the clout. I said as much.

Wait, since when YouTube is supposed to use DRM? I just downloaded 5 videos with DownloadHelper today.

It probably will be once DRM/EME is available in every browser. At least the chances are increasing, and that's exactly why making DRM ubiquituous and easily accessible is such a bad idea.

The problem is not that Mozilla implementing EME removes leverage to force Netflix into abandoning DRM (this won't happen anyway anytime soon), the problem is that once DRM is readily available without a large technological investment and without losing too many users, virtually everyone will use it for virtually everything, simply because there is little to none incentive not to do it, from a publisher's perspective.

Some, but not all, YouTube videos use DRM. It's up to the person posting the video.