Being the guy who sparked this whole thing, I guess it's time I weigh in with my stance.
In line with the consensus given in the latest in the years of discussions on this topic, they should be closed. ALL of them.
After literally years of the community hating and hammering these questions with close votes and downvotes, they are explicitly off-topic. They no longer have tags, because the existence of those tags was being used as justification for asking new questions about them. Likewise, the existence of open questions about admin panels is being used as justification for asking new ones.
Questions which even mention a control panel ought to be closed as well (like we currently allow for questions containing about "my home" network/PC/server/whatever), because they are a broken window in need of fixing.
All questions mentioning an administration panel will either be off topic for one of a number of reasons, or the administration panel will be entirely incidental, in which case, mention of the administration panel should removed from the question (also like we do with the rare topical, good question about someone's home network/server/whatever).
And, in fact, editing such a question to remove mention of the administration panel puts it into the reopen queue, where the community has a chance to decide whether it's currently topical or not. Part of the boiler plate added to closed questions by Stack Exchange even encourages this behavior by stating:
If this question can be reworded to fit the rules in the help center, please edit the question.
If it's genuinely off-topic, it will stay closed, if not, it will go through the provided mechanism remediating issues (like mention of a control panel) so it can be reopened.
Given the easy and repeated presence of this information, I find it extremely disheartening and troubling that this has become an issue, and see this as another example of Server Fault only getting any attention from the Community Management team when someone makes a baseless complaint about the long-held community standards on Server Fault.