I get your point, although I have been running a moderately popular open source project for iOS for a few years via GitHub, and it hasn't been as dramatic as you describe, by a long shot. Perhaps that says something about the culture of GitHub? Still, it's hard to imagine an Amiga project being significantly more heavy on the maintainer... And I seriously doubt that sloppy code in that case would cause problems professionally.
As for "fork off", it seems implied to me. If the author doesn't answer, and the license is appropriate, they already know what they can do.