The reasons why we close questions that are not about Ubuntu are really good reasons and we should keep doing that. I expressed my views on this in chat. To quote myself (because this meta post came at a time when I can't quite give it all the attention it deserves)
It seems to me totally unreasonable to make reviewers responsible for knowing exactly how Ubuntu differs from any other distro
There are some people who edit distro info out of questions because they have such awesome knowledge they know the problem isn't specific to the other distro, but I think it's a big problem to set a precedent for doing that or a policy for doing that. If non-super knowledgeable people who just had the vague or wrong idea that something was the same on Ubuntu and Mint were doing that, it would be a really unmanageable situation for reviewers and probably affect the site quality badly over time.
We don't close questions that are specific to EOL versions and that makes sense because we know what has changed between Ubuntu versions - that information is easily available, and somewhat embodied on the site, but the differences between even similar distros are subtle, myriad and not documented in any accessible way anywhere.
To summarise, we need a simple policy for deciding whether something is or is not about Ubuntu. We cannot have a policy that requires everyone who reviews to have a high level of expertise on distros that are not Ubuntu.
