I use grammarly to avoid citations from the grammar police like this for professional writing but not for HN. You understood what I meant so since this is a comments section keep the policing and unsolicited advice to oneself.
You're welcome.
It seems to be a result of they as a gender neutral singular pronoun. Which has a long history. Here oneself also works, perhaps even is more correct, but with the increased prominence of them as a singular pronoun, I can see why people write it like this.
Hesitates to venture that "more correct" isn't itself great English ... :)
I prefer it over correcter, and happen to believe there are various degrees of correct.
Grammar purists consider “correct” to be an absolute non-gradable adjective, I believe - though colloquially have at it and do whatever suits your written voice. I only mentioned it in contrast to the insistence that, er, one should use one rather than them - which to my written voice is a tad too formal.