First, we want to celebrate the change you used as your example! That change meets our need for inclusion. And we agree with you that inclusion is a universal human need.
What we feel might be left out of the description of “changes in society requiring new ways of expressing things” is the human toll in pushing for the use of “they” as a pronoun for a non-binary individual: People struggle to get their identities recognized; they are frequently ostracized and outcast and die because society does not recognize or validate who they are or how they represent themselves; they are still suffering and dying, despite the dialect of Canadian news readers. The change in language to allow “they/them” to be someone’s pronouns can be life-affirming.
Our friends on this thread who problematize the use of the word “citizen” are expressing “citizen’s” lack of representation, a sometimes life-and-death struggle to be seen and heard, a desire to be included via the use of language.
You point out many ways the word “citizen” is used and you stated, “there isn’t even much need to redefine.” Your examples of broader understanding of the word “citizen” may prove helpful to someone who objects to the word. Also, your understanding of the word may not match the lived experience of someone who feels excluded by the word “citizen.” There may be a divide. If so, how can we bridge it?
We want the people who posted about concerns with the widely used term “citizen science” to feel seen and heard–whether or not we agree with the concerns (we do). We want to tell them “we hear you” (which we believe is also a universal need–to be seen and heard).
We also want you to feel seen and heard. You propose there is a broader meaning of the word “citizen,.” such as a member of a community embodied by citizenship awards. And that the word “science” is the one being misapplied in “citizen science.”
Maybe for some of the same reasons that led Canadian new readers to use “they” in reference to a singular person?