Glad none of the posts mentioned are mine, Norah. Only one of them gives a hint and still isn't much of a giveaway as regards the puzzle as a whole.
I get the impression people come to the Listener thread for three reasons: (a) they've finished and want to see others' opinions and/or offer help (b) they're stuck on one or more clues (c) after several hours or even days, they can't see the final step required to complete the endgame. The issue is how much, if any, help we should ask for or offer those in the last category. I know from experience how helpful it is to get a final nudge over the finishing line - NOT "the theme is US presidents" but perhaps "you need to think laterally about the message from the extra letters" or some such. It's very hard to strike a balance, as I found when I tried to help a few posters with the music part of Skylark's music puzzle.
I will, of course, respect site policy, but I fear that people who need a bit of a nudge to get that last bit of highlighting after 20 hours of grid staring may take their business elsewhere if they can't get it here. Perhaps there should be a "May contain hints to the theme" thread?
TL;DR: I don't know what the answer is.