Operation Ark's mission plan
I realize that I've only read the book a time or two, but I could have sworn that I put in a passage that ah, yes. Here it is.
"One way to do that would be to maintain a preelectric level of technology on our new home for at least the next three or four centuries, avoiding any betraying emissions while preserving the records of our earlier history and the history of our war with the Gbaba. Assuming we could convince Langhorne, or at least a majority of the Administrative Council, to go along with us, we would also place two or three of the expedition's ships in completely powered-down orbits somewhere in our destination star system, where they'd be only a handful of additional asteroids without any active emissions, impossible to detect or differentiate from any other hunk of rock without direct physical examination, but available for recovery once indigenous spaceflight was redeveloped. They would serve as an enormous bootstrap for technological advancement, and they'd also provide a yardstick by which to evaluate the relative capabilities of later, further developments."
His holographic face grimaced, his eyes bitter.
"That was essentially what the original mission plan for Operation Ark called for, and if Halversen had been in command, it's what would have been done "
All jesting aside, what I certainly meant to imply here was that the original mission plan for Operation Ark was still officially in place when Langhorne was chosen to head the mission. That's why he spent 10 years rearranging the command structure of the entire expedition and packing his Council of advisers while Shan-wei got on with terraforming Safehold. All those machinations were designed to put him in a position which would allow him to so -- do what the original mission plan specifically called for him not to do -- that is, to create a society in which the demolition of all technology would also necessarily mean that the people on the planet in years to come had no idea that the Gbaba were out there. That, after all, is the real crux of Shan-wei and Commodore Pei's pragmatic opposition to his plans. They have plenty of moral reasons for thinking that what he's doing is both wrong and evil, but they might have been able to stomach that, at least in the short term, if they hadn't been afraid (with excellent reason) that technology was eventually going to reemerge no matter what Langhorne did, and when that happened, without knowledge of the Gbaba, the human race would run into the Interstellar Orkin a second time, and that it probably wouldn't be lucky enough to survive this time around.
Now, whether Langhorne and Bédard and the others were insane, rather than simply incredibly arrogant, is another question. They were definitely the spiritual heirs of the "Technology Is Evil" crowd. They believed that humanity had brought its destruction on itself, and that the Gbaba were simply the consequence of mankind's technological hubris. So, in a sense, they saw the Gbaba as a justification for their own anti-technology crusade. How much of that would have been the case had humanity not been facing extinction for most, if not all, of their own lifetime, is, again, another question. People who find themselves in hopeless situations generally also find themselves trying to find an explanation for how they got there, and usually, at least some of them are going to come to the conclusion that "it's our fault." It doesn't have to be a logical conclusion; it's simply one that turns up again and again in the human psyche. So it's entirely possible that in a civilization which hadn't faced extinction because it's technology had brought it to the attention of a more powerful, more advanced species with a Really Bad Attitude, they might not have felt that way about their own technology. However they got there, however, they saw this as their opportunity to make humanity over by seeing to it that all that evil technology never reemerged, and like many true believers, they were able to close their eyes to any possibility that would have invalidated their own ideological structure.