@awnlee jawking
However 'they' has long been used for a person of unknown gender so it's a logical extension.
This is a slightly different usage (despite MW's objections, as it's applied to single individuals, rather than 'groups numbering into the millions'. If a person is uncomfortable being labeled as either male or female, it's now considered, when requested, to refer to them simply as 'they', rather than pigeon holing them.
Trust me, these people don't use that pronoun amongst themselves, but for the more judgmental in their lives, they're putting distance between their personal and public lives, telling them to 'keep your distance' until they learn to behave in civilized society.
This is mainly a war being fought among the old-folk like us, as most younger adults have no trouble with it. They simply don't expect everyone to fit in the old binary standards, and for many people to flow from one to the other until they finally find a label which fits them more naturally.
However, those of us who've had those same standards foisted on us whether we wanted them or not, have a hard time casting them aside now that the rest of the modern world is casting them aside.
Personally, if in doubt, I'll ask someone how they want me to refer to them. If they identify as male or female, as most do, they'll tell me. If they prefer something else (though rarely "they"), they'll tell me that too. But if you ask an older person, they'll stare at you like your hair is on fire.