> Report the God Damn bug upstream on behalf of your user.
What if the maintainer can't reproduce the issue or doesn't personally care about the issue nearly as much as you do? The maintainer is not always the best person to forward things upstream. *You* care and have the data and are more useful on the upstream bug that the aforementioned maintainer. With the inability to tack other users onto the CC list in most bug trackers I've seen, both the maintainer and the user have to go to the bug anyways. A maintainer's time is not well spent playing messenger between upstream and users that have encountered some bug just because the user cares about a bug, yet not enough to talk directly with upstream.
That said, if the issue is a common one or the maintainer can provide more information because they either know the code well enough to tell or dug a little deeper, then they might be a better fit for filing upstream.
They should care, but they don't have to care as much as users would like if it's some corner case.