They has been used as a singular pronoun for centuries. I think your real issue is that you don’t like singular they being used for people who don’t identify as male or female.
www.merriam-webster.com/words-at-play/singular-nonbinary-they
In an 1881 letter, Emily Dickinson wrote "Almost anyone under the circumstances would have doubted if [the letter] were theirs, or indeed if they were themself." People have used singular 'they' to describe someone whose gender is unknown for a long time, but the nonbinary use of 'they' is relatively new.
Much has been written on they, and we aren’t going to attempt to cover it here. We will note that they has been in consistent use as a singular pronoun since the late 1300s; that the development of singular they mirrors the development of the singular you from the plural you, yet we don’t complain that singular you is ungrammatical; and that regardless of what detractors say, nearly everyone uses the singular they in casual conversation and often in formal writing.
They is taking on a new use, however: as a pronoun of choice for someone who doesn’t identify as either male or female. This is a different use than the traditional singular they, which is used to refer to a person whose gender isn’t known or isn’t important in the context, as in the example above. The new use of they is direct, and it is for a person whose gender is known or knowable, but who does not identify as male or female. If I were introducing a friend who preferred to use the pronoun they, I would say, “This is my friend, Jay. I met them at work.”