You can download the most recent version of the YouTube-DL code from Wayback Machine here: https://web.archive.org/web/20201018144703/https://github.co... Fuck the RIAA
It was really a matter of time. I'm sure most of us were already amazed it lasted this long - and it did because it remained a relatively obscure tool for years.
It's also the case that the development of subversive/illegal tools requires a certain amount of subterfuge and sneakiness that the youtube-dl developers apparently weren't ready to engage in. While this is understandable, it also underscores the fact that such tools live on borrowed time (as does, I would argue, general-purpose computing itself).