To be fair, this particular corner of English is a nightmare for native speakers, much less folks coming to it as a second (or more) language.
The term “nightmare” is worse than wild hyperbole. Native speakers of social classes corresponding to most of these characters are fairly well-read and surrounded by people who use the proper forms.
[1] For non-native translators, reference books are available, and one can create tables and pin these to the wall; and [2] even a broken clock is right twice a day, whereas these failures are consistent, a result of mis-learning.
The real problem is of people thinking that they can learn English from informal Internet communication, which is largely with other non-native writers and with under-educated native speakers.
The results actually works well enough when the translation is dialogue (rather than impersonal narration) and the characters are supposed to be under-educated; but most of these characters are suppose to have gone or be going through a demanding educational system.