高齢者, 老人 and 年寄り: reading older people in context
Compare handrail users and teachers of old games with an elderly person offered a seat and a villager describing life in the past. A grandfather's dislike of being treated as old is a particular reaction.
高齢者 as users and teachers
高齢者 (こうれいしゃ) identifies older people. In “高齢者も利用しやすいよう入口に手すりを付けた。” (“We installed a handrail at the entrance so older people could use it easily.”), a handrail was installed so older people could use the entrance easily. 利用しやすいよう states the purpose, rather than verified ease of use for every visitor.
In “学生たちは地域の高齢者から昔の遊びを教わった。” (“The students learned old games from elderly people in the community.”), students learned old games from elderly people in the community. The older people are the ones teaching those games; the name alone does not determine their abilities.
老人 in a seat and forest scene
老人 (ろうじん) means elderly person. In “杖をついた老人に席を譲った。” (“I gave up my seat to an elderly person with a cane.”), the speaker gave up a seat to an elderly person with a cane. The cane is a detail about the person in this scene.
In “物語の老人は森の道をよく知っていた。” (“The elderly person in the story knew the forest paths well.”), the elderly person in the story knew the forest paths well. 老人 identifies the person, while 森の道をよく知っていた describes that character's knowledge.
年寄り and an individual's response
年寄り (としより) means an elderly or old person. In “村の年寄りから昔の暮らしについて聞いた。” (“I heard about life in the past from an elderly villager.”), the speaker heard about past life from an elderly villager. The word identifies the person telling the speaker about that life.
In “年寄り扱いされるのを祖父は嫌がっている。” (“My grandfather dislikes being treated like an old man.”), the grandfather dislikes being treated like an old man. Read that response to 年寄り扱い as this grandfather's reaction, rather than turning every use of 年寄り into an insult.
Does the grandfather's dislike of 年寄り扱い make every use of 年寄り an insult?
Show the answer and why
No. This sentence describes the grandfather's particular reaction to being treated as old. It does not supply a universal rule for every use, including the separate example about hearing past life from an elderly villager.