I would have far more sympathy if their energies were about mittigation of the effects of construction. There are some concerns that I"ve heard over the years - increased traffic, issues with disposal of spoil, loss of footpath or cycle routes, etc.
Sadly those complaints are drowned out by those rich landowners in the Chilterns who claim they want high speed rail, just not on this route - e.g. High Speed UK. I.e. they want it in someone else's back yard.
The 'rich landowners in the Chilterns' (mostly people whose wealth and landowning is that they own their own house in Great Missenden or Denham - which are relatively cheap parts of the area) don't give two hoots about High Speed UK or any other alternative routings other than 'no build'. They are BANANAs, not NIMBYs. They don't want it in someone else's backyard, they don't want it built at all. They definitely do not claim they want High Speed Rail - they are aggressively opposed to the concept let alone the detail. There are genuine NIMBYs with genuine complaints about the line going through their backyards, but they were drowned out by the Built Absolutely Nothing Anywhere Near Anything people who have sought to attack the line by taking outlandish back of fag pack calculations by people throwing in Crossrail 2, NPR, etc and then doubling the lot for good measure and by pushing the fake news of "get to Birmingham 15 minutes quicker".
The Chilterns Full Tunnel option, removing the damaging South Heath portal (which will then be covered over with green tunnel, but the issue is the years of construction right next to/in people's backyards) and Wendover Dean viaduct by linking two tunnels, was only published by Bucks CC/Chiltern DC just before the hybrid bill was due to pass - way too late to be considered seriously. Why did it take so long? Because they listened to the vocal Great Missenden mob who will barely be affected (there might be some more traffic on the A413 that bypasses their town*) rather than the South Heath concerned citizens up the hill who have been affected by the line's route. The Full Tunnel option was the Hail Mary play - the last ditch effort to do something for blighted residents when the councils had spent a good 5+ years failing them by focusing on getting the cancellation of the whole project.
It was HS2 themselves that rerouted and lengthened the tunnel to avoid Old Amersham** - those valid complaints about impact were addressed by the local lobbying group not by suggesting alternative routes keeping away from the town (unlike the Grand Union Canal, WCML, GCML (yes I know it goes through Amersham - but it was built it climbed a valley side to avoid it, and made the Met to Chesham go up to the top of the valley side before going back down, so that they could share a route as much as possible***) and M1 which were successfully blocked from the area by either NIMBY campaigns or by NIMBY campaigns working with people lobbying to have the route serve them) but by covering the countryside with cutout white elephants. HS2 thankfully took the initiative to address the valid NIMBY concerns in the hopes that it would stop the opposition (it did help quell the sensible Amersham Anger as legit local complaints were dealt with), having not realised that the vocal opposition was BANANAs who cared about their house prices and their failure to sell their unaffected houses for what they wanted (which would have been expensive even at the height of the boom a couple of years before - and were absurd in the depths of recession) because they wouldn't shut up with their unfounded fears about blight and how HS2 would ruin the area - not something a prospective buyer wants to hear!
The anti-HS2 big board at the A40/A412 junction in Denham has never been about the blight to the local area such as the two tunnel portals and Colne Valley Viaduct. It's always been about cost and pale pachyderms. I've never seen "save HOAC" on it or anything actually NIMBY in 10 years - the local issues don't matter (and sure, that part of Denham is some way off the route) and tweaks to route won't help - it's always, from day 1, about killing the concept itself for those people.
*A thing that HS2 themselves have worked to reduce, and that the Stop HS2 brigade have given no proposals to reduce other than "don't build it anywhere". Bucks CC/Chiltern DC have been active at mitigation reduction once they realised that they weren't going to cancel the railway but were terrible beforehand.
**And also Great Missenden, the home of the torches and pitchfork mob against HS2 - the line was originally to be down the hill next to the Missenden bypass in a deep cutting. They had a sound simulation of a train going by at the 2009 consultation event. You could barely hear it over the constant car noise. It was there, unlike what some conspiracy nut loudly slandered the staff with, but you really had to strain to actually hear it. I guess the lack of genuine impact was why they couldn't take a NIMBY line and had to turn their hate against the concept - because the impact on their town was laughable even before the reroute away that didn't sate their complaints.
***You can see it in the original station names - Amersham & Chesham Bois was built near Chesham Bois to serve Amersham, Chalfont & Latimer was on road near where a crossroad would take you to Chalfont St Giles or Latimer and Chorley Wood & Chenies was built in Chorleywood (which had by then become a small settlement and one word rather than just some trees) to serve Chenies (which remains a small settlement). It speaks of wanting to have two lines - one in each valley, but having one on top of the ridge.