People should move their youbube-dl repositories to servers hosted in Switzerland, where people are not criminalized when downloading content and making copies for personal use (even when copy protected).
I hate to break it to you but distribution of tools related to bypassing DRM/technical protection measures (which is what the RIAA takedown letter actually cited) is illegal in Switzerland and has been since 2006. Indeed, you can be sent to prison for it with a maximum tariff of a year in prison. https://www.admin.ch/opc/en/classified-compilation/19920251/...
EDIT: also note that it states "effective technological measures" ("Umgehung wirksamer technischer Massnahmen" in German); if there is no (effective) protection measure such as in Youtube then the referenced sanctions obviously don't apply (nulla poena sine lege).