This person seems to think using 'they' as a singular is somehow wrong in English.
That's not correct. It's been used since the 1500s and it was only when the wave of idiot Victoria grammar prescriptivists started throwing weight around that there was any dispute at all.
That's not correct. It's been used since the 1500s and it was only when the wave of idiot Victoria grammar prescriptivists started throwing weight around that there was any dispute at all.