Or to explain that and how they stopped a threat might reveal how much they know, who their informers are, what type of codes they can break, and hence make it

Or to explain that and how they stopped a threat might reveal how much they know, who their informers are, what type of codes they can break, and hence make it hard to stop the next one. If you tell Bad Guys™ (a) that and (b) how you stopped a previous attack, then the next set of Bad Guy™ will know not to make those mistakes.