The reason for the close is given in the yellow box under the question
"Bug reports and problems specific to development version of Ubuntu
should be reported on Launchpad so that developers can see, track and
fix these issues."
Bugs are explicitly off topic here, as per the help, meaning this is not a "valid" question.
You state "It's incredibly unhelpful" but it is quite the opposite. Firstly the question had no answer, so won't be helping you or anyone else find a solution but the reason for closing gives the link to the correct place to report the bug and that is very helpful, seriously, go and report it on Launchpad, the developers will see it and they are the ones who can fix the issue, the more of you that go and report a bug, the more priority the devs will give to it and the quicker it will be fixed.