The Just Culture depends on the agenda of the day. If the message can be shaped or used to support something that the wider chain can support then Just Culture works. If the message or event is deeply uncomfortable for someone in the higher echelons then the retribution can be brutal, even if someone is expressing an airworthiness concern.
I have known people to removed from post within a day for speaking out with a genuine concern, even if that person has documented and referenced all the supporting evidence.
It can be brutal at times if someone highlights something that can embarrass a star ranking officer.