From what I've gathered through various comments etc on EL&U, here are the main objections posed by those who have been associated with the site longer than I have:
The site exists as a repository for future reference, so questions that are left open should be those that show promise of helping future visitors - that is a distinguishing factor between Stack Exchange's philosophy and that of discussion boards. It's been expressed that naming one person's variable or UI control doesn't help with naming that of someone else.
The English doesn't matter in this cases. For programming variables - and the same applies to some extent to the naming of UI elements - the actual name given doesn't really matter. You might call a variable index or i or englishlanguageandusage, and it will increment/assign/etc just as well.
On #2, setting aside the issue of readability for the time being, I think it's important to consider whether we're really talking about English "as she is spoke". Traditionally, we'd consider the context of 'English' to be phrases, sentences, paragraphs, and so on. But with UI elements, there's also the visual aspect. For example, a control might be labelled "Left" or "Previous" or "Prev" or "Before", but it might just as well be labelled "<" or be given a graphical overlay. The issue here is where to draw the line between English and UI.
That line is really the heart of the matter. EL&U was intended as a community for fluent English speakers (per the tour: linguists, etymologists, and serious English language enthusiasts) to discuss the language. Whether the label still fits is a separate issue, but to me, the fundamental criterion for a question to be considered on-topic is that it must fundamentally address the English language. That's not to say that other criteria don't apply; it's just that if a question is more about UI aesthetics than about English, then it's on shaky ground. If it is fundamentally about English, then whether UI comes into play as well is irrelevant.
I'll comment on a couple of recent examples:
This question asks for a word for a menu item to "merge the configuration and the selection steps in the UI development".
Let's ignore the menu item and consider the language-related content of the question as it stands at the time of this Meta answer. All that is left is a request for a hypernym of configure and select.
Single word requests are much maligned as it stands. There is a checklist provided in the tag info, together with other advice about asking such questions to help keep such questions relevant to the community's charter, but these guidelines are often ignored.
There's no discussion about the sense of each term or what nuance the hypernym should elicit, and there's no sample sentence or linguistic context in which the term should fit. This is a common failing of 'naming' questions - the lack of an English language context.
If the question had followed the guidelines of the SWR checklist, it might have clarified why configure and select should have a meaningful hypernym and highlighted the point(s) that would have interested "linguists, etymologists, [or] serious English language enthusiasts".
This question asks whether "clear" or "reset" works better within the phrase "clear/reset unsuccessful attempts" and invites short alternatives that express the idea "sets the count of unsuccessful login attempts to zero".
Although the question uses specialised technical terms (e.g. using clear to mean "set to zero"), there is significantly more English language content to this question than to the previous question. I think this question would require a lot more justification for someone to vote to close it.
Summary Whether a naming question is on-topic depends heavily on whether the question justifies itself as being about the English language in a 'language' context, as opposed to merely deploying English terms as labels.