I've used reference-request
a few times myself. My view of its proper use would include giving background to the result or other subject matter which the reference refers to, motivating why the subject itself is interesting to look into. However, that's also my opinion regarding all questions. Simply asking "I need a reference for problem X" seems on a par for brusqueness as simply asking "Can we detect jeejaws in 2-whatsis-graphs in $O(n^{3.1})$ time?" without further elaboration.
In a field as broad and sometimes as particular as Theoretical Computer Science, even those who mostly ask questions can provide value for the website by adding context so that those unfamiliar with a particular subject can learn something new from the question alone. My attitude towards the reference-request
tag is informed by the fact that the field is wide, with many narrow crevices. You certainly don't want reference requests to dominate, because this site is not meant to be a library. But for a narrow enough topic, sometimes the only adequate librarian is someone who is intimately familiar with the topic.
I suppose having a specific reference-request
tag is not necessary to allow such questions on here, but I would be unhappy if such questions were disallowed. If there were too many of them, I would suppose that it would indicate deeper problems with the forum.