[defrost]

English frequently uses they to refer to a singular person.

It's been common place all my life and that's going on six decades now.

'Merkin English, however, likely has prescriptive rails and a lingering shrinking horror stemming from the inappropriate touch of Webster.

> those old paper books are more accurate guides to how people use it than their ideologically-driven on-line counterparts.

Exactly - see the full OED (Oxford English Dictionary) entry on the long historic use of 'they' over seven centuries and the many ways in which it has been (and continuous to be) used contemporaneously both as singular and plural.