They wrote Beijing as 北京市 because that's how it showed up in the database. But they also wrote "BreedReady" because that's how that key also showed up in the database; all the DB keys are English, apparently (https://twitter.com/0xDUDE/status/1104482014202351616). I'd assume it's designed around good ol' fashion fear that not all languages accessing the DB are Unicode-capable for labels and identifiers.

NextWeb's reporting on the Twitter thread suggests that the phrase may be a Chinese attempt to translate to English a Chinese word meaning "woman of child-bearing age" [https://thenextweb.com/tech/2019/03/11/1-8m-chinese-women-de...], but we don't actually know because we have no primary source on what character was translated as "BreedReady."