I think you are being too strict. English doesn't have a dedicated "impersonal gender" in all cases. Sometimes it is "one", but often plural is used whenever both -- masculine and feminine -- is being addressed.

Here's more on that: https://parentingpatch.com/one-must-wash-hands-using-singular-impersonal/

Hi Chris, thanks for the response. I don't think I am being 'too strict'. I made the distinction between 'common usage' and correct English. Your random American blogger is simply offering another asserted opinion, which happens to agree with yours, I think. As an A level English examiner for nearly 40 years, I accept I'm probably too sensitive to it, but I think on such a wonderful language learning site as this is, it is important to maintain these distinctions. Goodness me, we will be reading 'Crewe are promoted' next!

Hi Steve, don't like my blogger as a source? Alright, here is heavier artillery: https://en.wikipedia.org/wiki/Singular_they

This article details that singular they has been in use since well before Shakespeare. Today, in contemporary Canadian English, for example, its use is even encouraged: the Canadian government advises the use of themselves for the singular in legislative texts.

It seems that staunch opposition of they being used in this way is denying the obvious: it already has become an integral part of the English language -- and not just at the informal level. This is even more pertinent since with rising acknowledgement of sexual diversity, we need more creative use of personal pronouns.

I, too, am a stickler for language and am often called a conservationist. But in this case, the use of they as a singular pronoun makes perfect sense: enriching the language, without diluting its precision. And this already since the 14th century!

Good response, Chris. My heavy artillery is Cambridge Dictionary:

When we want to refer back to everyone or everybody and we don’t know if everyone is male or female, we use him or her and his or her. In informal styles, we use plural pronouns they, their and them:

Everybody has a team leader in charge of him or her.

Not everyone has his or her own desk.

Everyone has to climb to the top. When they get to the top, they have to blow their whistle. (more informal)

Has everyone got their coats? (more informal)

I was also involved in drafting tax legislation at one time and such distinctions are très importantes in that world, where the disjunct between singular and plural would have been a thoroughfare through which many a tax evader would have gleefully galloped! But perhaps we had better not clutter up this site any more with our arcane discussions.