In the limit, you get "communication is impossible"

Sure. But I don't see any reason to think we're near the limit in this case. Pius XII was pope and I'm not, true enough. But we're reasonably close in time (he was born a little less than 100 years before me), from reasonably similar cultures (both Western European), of at least overlapping religious backgrounds (my family was RC and I was a Christian although not an RC for something like 30 years) -- this all seems to me like the sort of situation in which interpretation should be less problematic than usual.

Why not be charitable, then?

I really don't see that I'm being uncharitable. If you insist that I am and ask why, I suppose the answer is that in cases of conflict I'd rather be accurate than charitable; I see the PoC as (inter alia) a tool for avoiding wrongness that comes from assuming people who disagree with you are evil or stupid. But I'm not (I promise) assuming that either Pius XII or John Paul II were evil or stupid, and my real answer to your question is that I don't see how I'm failing to be charitable.

there is no profit in making falsifiable claims

There is profit (if we must put it that way) in making correct claims, and if a pope thinks that theological considerations lead to a particular empirical claim then I don't expect him to refuse to state it on those grounds. (It seems to me that expecting otherwise is the less charitable position.) And there is profit (again, if we must put it that way) in making claims that sound confident and informative rather than vague.

But, as it happens, I am not (I think) claiming that the RCC's official documents make a falsifiable claim that is incompatible with naturalistic evolution. I am claiming that the position they state is deliberately less specific than naturalistic evolution; in particular, you will search in vain for any statement that evolution proceeds as if there were no god guiding it. Or that it probably does. Or, I think, even that it might do. And that the official documents give the impression (to me, at least) that their authors think it probably doesn't.

I repeat that none of that seems to me uncharitable. I am saying that the RCC has declined to make official statements that would likely be interpreted as endorsements of godlessness and as incompatible with their past positions, and that the RCC's position on aspects of evolution that are hard to get clear empirical evidence about is probably shaped by the religious doctrines that it endorses. All of which is as it should be, conditional on its being the sort of organization it is.