The rule about using "proper" English is about how we talk during our posts. For example, we shdn't tok lik ths b/c ppl might not understand. It's not about what we read in game--if it were, 90% of the Lominsan population would be reportable!
I think of it this way...Report typos for sure. Probably report awkward wordings and see what other people think. But we don't have to report things that are non-standard but still not-wrong, because not everyone in Eorzea (or Norvrandt) speaks with perfect academically prescribed grammar, and the writers and localizers do take character into account when writing or translating dialog. If a real world native English speaker would use a particular grammatical construct, prescriptions be damned, it's okay for an in-game character to use it.
So in this particular case, it's probably okay for the mayor of a small pastoral village to use "hung" to refer to someone who has been "hanged", just as it's okay for someone with higher expectations of people's grammar to cringe at such a use.