Everybody except the person making the polite request.
Then I'm part of your "us" group, and I am quite happy to accommodate any sincere request to refer to someone with pronouns and any other means that conforms to their request. As a fellow member of your group, I would say that I don't see why we should have a problem with that. It may seem awkward, but it doesn't do us any serious injury to be polite.
The pronoun of a person isn't determined by society nor the individual's choice. It is determined by the individual's genetics. It is an innate objective reality.
Shaul, pronoun usage is determined by a speech community, not genetics. It is a social convention. Gender-based pronoun usage goes back well before anyone knew anything about genes, and gender identity problems were simply a taboo subject of discussion. Given the changing times, we can talk about it openly now and come to an understanding of how to deal with it. We've already changed pronoun usage a little to accommodate neutral references to heterosexual gender, since some of us find it awkward to always have to choose between male or female pronoun reference in sentences like "Everyone forgot his/her/their textbook". Many writing style guides have even begun to approve the use of "their" rather than a singular pronoun in such cases. We are lucky not to have gender marking on plural pronouns, so there is no logical reason why English should need it for singular usage.
When you say "they", What group are you referring to?
I believe that there was a clear antecedent to the pronoun in the post you quoted, so that should be your answer. I was referring to people who frame gender pronoun usage as a "demand" rather than a request.