Just a thought... Owing to the plethora of published information (official and commercial) it is one hell of a job for a unit to keep up-to-date with all that is published on their behalf (especially UK Mil Units that have two sets of Docs to contend with). From experience I know that even high-lighting an error to the publisher cannot always guarantee an accurate ammendment (often your words are paraphrased).
Took over two years to get the world to acknolwedge a change of APP Freq at my last Tower... we had to resort to having a dialable, standby radio tuned to the old freq on loudspeaker to pick up the misinformed (of course none of those were using out-of-date info were they?)
Might also have been workload? If handling a problem on that frequency (or maybe UHF) the controller might want to offload traffic to another controller?
In otherwords plenty of reasons, the snappy reply might not be best practice - but we all have difficult days at work don't we?