On Naming Others
I have always tried to respect other people of good will, and will try to call them by whatever name or label they choose. If an individual asked to be addressed as Moritmer Snerd, I would hold my personal opinion private (depending on our relationship--a close friend might get amused questions about reasons before I said "glad to meet you, Mortimer"), and accomodate this new bit of reality, while requesting forbearance as my tongue and brain learned a new coordination.
I do have some knee-jerk responses baked into my psyche with regard to the English grammar I learned at my mother's knee; she gifted me with a standard of usage that allowed me to correctly choose answers on tests and quizzes by ear: if it sounded right, it was. I still use my own personal standard of courtesy when addressing or referring to others in a public setting, and try very hard to realign the brain pathways that protest things like pronoun changes.
I accept linguists' assertion that "them" has been used as a singular pronoun in English at other times in history, and am willing, however challenged, to school my social exchanges in that regard. I know I have probably used it that way myself--but I often use "incorrect" English while knowing that it is incorrect. "That ain't right!" comes off my lips in casual conversation, but it's always accompanied by "it certainly isn't!" inside my head.
I also believe that I can still find ways to keep my poor synapses happy without disrespecting other people's sensibilities and sensitivities, and will continue to work as hard as I can to do so. It is only basic courtesy.