Questions about local tools for downloading from YouTube should be, prima facie, on topic: questions should be judged on technical merits
Back in 2011, the question arose with regards to removing DRM. I believe the situation is analogous.
From the question:
I just asked a question about how to remove DRM from Kindle books that I had purchased and it was promptly closed by the moderator studiohack with the following comment:
We don't encourage this kind of behavior here on Super User, thus off-topic.
With the response:
Unless it is a clear call for warez, discussion of DRM should be given the benefit of the doubt.
I would hate for us to censor legitimate, technical discussion just because what we're talking about happens to be illegal in some jurisdictions. We should have the same standards as universities: we should defend people's rights to free speech.
It should be noted that this answer literally has unanimous consensus: 153 upvotes, zero downvotes.
The situation is analogous
Consider the perspective of a user. They want to consume video content on their machine. Whether that is by removing DRM to play back in the video player/device of their choice, or by downloading to play back in the video player/device of their choice.
Presently, the situation has been "vote/deal with it on a case-by-case basis"
There was another Meta SU question, which broadly took in things such as 'EULAs, NDAs and other third-party agreements'. In that case, the original main site question that prompted the meta question was about OS X on VMware.
shlck's answer started:
This is not a real "answer" to your question nor official policy, so please bear with me when I'm rambling a little.
(...large parts about EULAs etc snipped...)
Interestingly, in 2009, Jeff said, when asked how questions that break ToS or other policies should be handled:
Yes please flag profusely! That's what flagging is there for, and we look at all of them!
As you can see, even here, there's no agreement and the decision was forwarded to moderators.
with the outcome in comments:
So in essence, we each vote our conscience on such questions, on a case-by-case basis? – aroth Aug 28 '12 at 1:22
and the reply:
In fact, yes, that's always been the case and there's no other official policy. Of course, unless something is clearly about downloading warez, black hat hacking or software cracking, we'll probably give it the benefit of doubt. Hackintosh question are a bit of an exception where we have a policy that's not just about breaking of the license but rather the kinds of questions we don't want to have. – slhck Aug 28 '12 at 7:24
We are not here to police the internet
Secondarily, we should not be here to police others adherence or otherwise to third party TOS. What happens between YouTube and a user is between those two parties; it is not for us to decide what is acceptable. Questions should be judged on the technical merits, not an interpretation of an agreement between other parties. There are good reasons for this, but they are beyond the scope of this question, which is specifically about YouTube videos.
Questions about web services that offer download functionality remain off topic
For the sake of completeness, it should be noted that there are many web services that offer the functionality to download from YouTube. As with any remote web service, these are off-topic for Super User.