Different people have different eyesight and it changes with age. It's not just about near- and far-sightedness, it's about temporal resolution as well, except you can't correct this with glasses. Most people can't see the difference between 240Hz and 480Hz, but some clearly can. And most people can see the difference between 60Hz and 120Hz, but some cannot, especially if they are 50+ years old.
Even if they can tell the difference, it might not seem as drastic for them as for younger folks. Additionally, even someone who has the physical ability to experience 120Hz, but never actually used 120Hz screen before, might still not care because they don't know what they're missing. Once they use 120Hz screen a bit, they will not want to go back to 60Hz, but for now it's totally fine!