That it's it's better to publish the garbage data than to not publish it though. I would worry about complaining too much lest they just decide to stop publishing it because it creates bad PR.

As long as the garbage data is authentic and the method used to produce it is adequately detailed, I agree with you that: "it's better to publish the garbage data than to not publish it"

But fake data or garbage data without the method, is better left unpublished !

Hard disagree on that. They just need a basic smell test before they put it out.

Agree. Maybe just add a Disclaimer.md file.