You're so sure that everyone's night vision is that different and yours is so terrible? Under what circumstances? How often in the last five years have you been in near total darkness for more than 20-30 minutes, with no lights around except starlight? My night vision is crappy when I first walk outside of my house, but after 30 minutes of stargazing or other no-light activity, it is amazing how much better I can see than I could just 15-20 minutes before. If you or any other person has such poor night vision that a bright flashlight is required to be on for safety sake so you don't trip and fall, then I'd suggest taking night hikes with a group of nature lovers is not something you should be participating in.
The point about careful flashlight usage on a nighthike is twofold, how bright the lights are that you're using, and where they are pointed. No one is likely to object if you have a very dim red led flashlight or headlamp pointed straight down at your feet so you don't trip and fall. What people object to is when the light is too bright or is a distraction such that their night-adapted vision is destroyed because someone inadvertantly (or on purpose) flashes a light around.
On a slightly related topic, I used to attend an annual 4-day music festival that had 80,000+ people camping overnight in the hills of Pennsylvania. After the last concert at around midnight, there were tens of thousands of people streaming back to their campsites along unlit dirt roads and paths. Some of the kids would flash their "bright" 3 or 4D cell Mags in peoples faces either because they wanted to see who was talking to them (stupid) or because they wanted to just be immature and show off their bright flashlight (even more stupid). I would typically use a dim LED headlamp pointed down to see where I was going, or sometimes the LED's from my A2 pointed at the ground. The second a kid would flash me or someone in my group with their Mag or other flashlight, I'd hit them in the face with the light from the incan bulb on the A2 or with an SF 9P, and give them a mild warning. WOrked like a charm.