I agree completely. I also know that distros patch packages.
But for unzip the situation is particularly bad because it has no maintainer. Normally, you would raise feature requests for basic functionality upstream and once added, the maintainer would cut a new release. So software with the same version number generally, but not always, behaves similarly across distros.
But for unzip, because upstream is unmaintained, distro maintainers started to add features while keeping the version number. So in the end you end up with different behavior for what looks like the same release.
But for unzip the situation is particularly bad because it has no maintainer. Normally, you would raise feature requests for basic functionality upstream and once added, the maintainer would cut a new release. So software with the same version number generally, but not always, behaves similarly across distros.
But for unzip, because upstream is unmaintained, distro maintainers started to add features while keeping the version number. So in the end you end up with different behavior for what looks like the same release.