The intent is not "in open source, the burden is on users to fix issues." Rather, the intent is "in open source, frustrated users have a potential recourse other than relying on the developers."
Unfortunately, the usual phrasing does not make this clear.
In the closed source world, it's perfectly normal when filing a bug report to get back a polite "we acknowledge that issue, but it isn't affecting much of the user community. In the interest of prioritizing our scarce development resources, we will not be addressing that issue on our current roadmap, unless it impacts a significantly larger fraction of our paying customer base."
In the open source world, I think the intent of "use the source, Luke" is to be shorthand for something similar:
"We acknowledge that issue, but it has not been reported by much of our user community. In the interest of prioritizing our scarce development resources, we will not be addressing that issue on our current roadmap, unless it impacts a significantly larger fraction of our user base. Please continue to report other bugs; all bug reports are valuable feedback, and we do fix many user-reported bugs based on our triage and prioritization processes. Note that, if this bug is sufficiently problematic for you, and you have the necessary skills and resources, you have the source! So you are welcome to fix this for yourself, should you be so inclined."
Unfortunately, frazzled developers are far more likely to give a curt response rather than spending the time to write up something more polite. FWIW, I'd be happy for anyone who wishes to use the wording I just used.
Again FWIW, my own experience is that both closed source and open source developers vary widely in their support level. As a for-instance, I found a problem with a certain closed-source device vendor's product not being RFC compliant, and therefore failing to properly inter-operate with an open-source management program. A coworker contacted the vendor as a (paying) customer, while I contacted the mailing list for the open-source software. The author of the open-source software emailed me a workaround within hours. My coworker is still waiting for a useful response from the vendor.
Conversely, we had several interoperability problems between a different vendor and a different open-source program. The vendor actually had already made a patch for one of the issues, but we couldn't deploy it. The maintainer of the open-source program refused to workaround one of the issues on their end, because the vendor had patched it, and we should just install the patch. While I didn't like the situation, this was a major problem for us, so I was motivated to hit the source. Because I had source, I was able to write my own patch.
Obviously, YMMV.