Yup, and as per the Internet's one golden rule (of which we have at least a dozen), "Do not (ab)use downvotes to disagree, put your disagreement in writing or stay silent".

It is frowned upon here, but not against the rules. Downvotes on HN should, optimally, only be used to downvote comments that truly do not add anything to the conversation constructively.

qwerty's comment, imo, was constructive, as that is a common use case of ytdl: to watch a video without being explicitly tracked by Youtube; although Youtube still does track you, but in ways that probably violate EU law, and might violate US law too.