Re: Is this just an English thing ?
The fact is though we see society use singular they all the time. Examples of perfectly ordinary usage of it include:
> “If anybody wants their admission fee back, they can get it at the door.”
"Anybody" designates a subset of admitees. To consider this to be a singular reference is to assume that at most one person may want a refund.
In fact, with any sufficiently large event, it is almost guaranteed that there will be more than one person who wants their money back.