"DRM does not work, so we'll back it up with a few laws criminalizing DRM circumvention." Reminds me of:
I'm sometimes baffled that people miss that point when it comes to internet security. The biggest real difference is the global nature of the internet and thus problems with jurisdiction, which obviously doesn't apply if both sides reside in the same jurisdiction.
Clearly what is most important is the intent. In this case, it is very clearly RIAA's intent to make the aforementioned videos obtainable publicly via the use of HTTP agents. Browsers are HTTP agents. youtube-dl is an HTTP agent. Either they are all infringing or they are all not infringing.
On the other hand, it is clearly the intent of my door and lock to keep people out.
There are other examples in the real world tho, where the distribution/creation of the tool is already illegal (e.g. certain weapons or explosives), because only reacting after damage is done is infeasible.
If fair use tells us that it's ok to use parts of copyrighted works for certain purposes, then there must be a legal avenue for obtaining those parts.
There is massive legitimate use for downloading videos, yet the alleged harm is purely monetary.