I think these questions invite low-quality, short, code-only answers and decrease the overall quality of questions on the site.
They are too narrowed down on a specific issue and leave very few possible answers, and can be answered with a mere comment.
I think the ought to be closed, ideally with a "too narrow" close reason.
I have forked @rolfl's query and added some information about the OP and their participation.
71 of the 76 rows returned involve an OP with < 500 rep score, and none involve a > 1K user. 27 involve an OP that has given a sign of life during the past month, and 31 were asked after 2013-01-01 (6 in 2014).
What comes out of this quick analysis is:
- A majority of these questions were asked in 2011-2012 when the site's scope wasn't as clear-cut as it is today.
- 47 of the 76 were first posts.
This isn't about the length of the question. The Singleton question, for example, is perfectly acceptable despite its 4 lines of code - it's about the scope of a question.
When all the OP wants to know is how a tiny little piece of code could be written better, the purpose of the site is thwarted and Do I want feedback about any or all facets of the code? doesn't hold anymore, because there's only 1 facet to review.
The same applies to longer questions that fill up a switch statement with dummy code and ask how could I refactor this switch block?.
I don't think this is what the site was created for. We want questions that include an entire method, or an entire class - enough code to actually review something. Giving all possible ways of rewriting 2 lines of code doesn't constitute a useful "review".
The number of answers given on a question, and the votes these answers receive, don't make it on-topic either. It's not even because it's a poor question. There are very interesting questions that would be on-topic on Programmers.SE, that have to be off-topic here.
There are other programming-related sites in the SE family, and sometimes the boundaries are foggy between two or more sites' scopes - there's a level of overlapping that's likely to occur. We need to know where to draw the line where CR's scope ends, and when a question would receive answers that would be more relevant / on-topic on another site. If a question's best answer is not a code review, it's probably not a code review question.