Do you have a source on that? That would be interesting if true, and makes me wonder how long they had planned that entry that gets continued. Was it written as of season 3, or was it always sitting around somewhere, but not included in the published diary for some reason?A few tiny snippets do not outweigh the outrageous number of discontinuities with the show + fwwm. For all we know (and I believe this happened), they gave those to JL to include, not the other way. Annie page is not in the book...because fwwm didn't exist yet.The people writing the lines do care, though. You see portions of the book someone took the time to write out in longhand in Laura's prop diary as she flips through it in FWWM. They even cared enough to continue an entry Jennifer wrote 25 years ago, which until then was partially unfinished, on-screen and legible in the new season, as Mr. Reindeer has tracked. They've also previously taken lines from the diary and had the actors read them aloud. Whether Lynch read it or not, which iirc has conflicting accounts, it's clear that the production itself has involved its content consistently over the course of each production, whether literally or performatively. If all we should pay attention to are TV+FWWM, then the diary or at least selections of it exists there already, anyway. And it's not as if the original series + movie were ever free of their own continuity strangeness.
Informing a performance doesn't make it useful for tracking dates for plot continuity. Also, no matter what informs a performance, it's still just saying the lines on the page, and if the people writing those lines don't care about the Diary, the result won't reflect it very much.
I still don't see why that should cause the entire diary to be thrown out, though. FWWM is as overwriting of prior established continuity in terms of the series as it is for the book. That's sort of always how TP canon has worked; it's canon until it isn't.
The creative forces, to me, have always clearly put stock in the expanded material. When you have Frost, who co-wrote the old and new season, rereading old material such as the Cooper autobio to refresh himself on his understanding of the character, I find it very hard to be dismissive of that output. When he even references events in the Access Guide (albeit paralleled to further hint at a diverging timeline) in his books, it's clear this content is at least informing his contributions to the material.