

Just because it’s open source doesn’t mean it’s necessarily open for all uses. His license explicitly denied using his code in packages. People did it anyway.
There exists pkgbuilds for arch and previously packages of the older GPL builds.
A pkgbuild is just a recipe for each users computer do do the stuff needed to fetch and or build publicly available software. It is copyright the writer of the recipe not the owner of the software thus fetched. That is to say the owner of foobar can’t copyright the functional equivalent of a bash script which does git clone and make install foobar.
The older versions thereof are still available under the GPL and aren’t subject to being removed.
Neither of these are actually subject to the authors whims. He doesn’t own the pkgbuild and if he chooses to offer the file to users they can download it either by manually git cloning it or having a script do it.
So no they didn’t “do it anyway”
The overwhelming majority of Linux users are on 4 distros + derivatives. Debian Fedora Arch Suse not “thousands”
Where would what end? Most actually open source projects just publish releases to source and provide as much or as little support as they feel like. Slap a github issues page up and tell every user that you are only interested in dealing with bugs in the most recent version in whatever official channel you prefer eg provide appimage of releases and insist that users reproduce and document bug.
Time wasted mostly wont even bother to create a github account and if they do close issues if they can’t follow directions.