I think you are reading too much into the proximity of exceptions and rules in the Catechism. Apparently you don’t want to see CCC 2488 and 2489 as exceptions to CCC
2483 just because it is not immediately adjacent. If the truth is absolutely sacred, then 2488 and 2489 would be hard to reconcile. So tell me, what is the proper interpretation of 2488 and 2489 that would not apply to the extreme cases mentioned earlier?
2488 and 2489 are not exceptions to the rule, and if you think they are then you’re misunderstanding what the rule is.
The rule is simply that everything we DO choose to communicate should be true as opposed to deceptive untruth.
The rule is not,as you seem to think, that we MUST comunicate absolutely everything we know to be true to anyone and everyone who asks us for information regardless of circumstance.
There’s a crucial and I hope obvious distinction between not telling the whole truth to someone (which is the sort of ‘discreet language’ that the Catechism permits) and telling a deceptive untruth (lying) to them, which IMHO it doesn’t. Lying isn’t discreet language, it’s deceptive language. Discretion is not the same thing as deliberate deception by way of total untruth.
2488 and 2489 are making the distinction clear, they are not making exceptions to anything.
If I can make an analogy - no-one would deny that the Eucharist is an absolute good, and that anyone who disrespects it commits sacrilege and serious sin.
However, not everyone has a RIGHT to the absolute good that is the Eucharist - those who are in mortal sin, for example, or non-Catholics.
So yes, the Eucharist can and indeed should be denied to some who would partake. But you can’t be disrespectful about the sacrament while exercising this prerogative. A priest can’t, for example, say to the person he’s denying ‘oh, you don’t want that, it’s just a cracker after all’.
This in effect is what you’re doing when, in the course of exercising your right to withhold the full truth from someone, you turn around and go further, and demean that truth by lying to them.