Mr Barrett was forced to resign as assistant treasurer amid a sex scandal last month, and later quit the Country Liberal Party, after it emerged he had sent lewd videos to a woman who was not his wife.
In the post Mr Barrett said he was speaking as the Member for Blain, a position he will hold until parliament is dissolved in just over a week.
“I spent a whole lot of time and effort with people trying to get some resolve for youth crime. I saw how angry people were and I see back on the Belamack (sic) page today the youth offenders are at it again,” Mr Barrett wrote.
“Spit hoods and restraint chairs stop kids from hurting themselves and others. Our corrections staff dont (sic) need to be spat on or threatened in their workplace. Is the whole system broken….. yes and has been for a very long time.”
He said there was no “easy answer”.
“But the media are utterly without accountability and hell bent on spraying vitriol on Government,” Mr Barrett continued.
“They feed on chaos. They love that they made (Minister for Corrections John) Elferink resign. They are sharks that frenzy without remorse or care for the human beings involved.”
He reserved particular fury for News Corp tabloid, which precipitated the scandal that forced him to resign, and for Darwin Mix 104.9 radio presenter Katie Wolfe.
In the comments section several people weighed in to defend local reporters.
“Wouldn’t it be nice if it wasn’t up to the media to keep politicians accountable, and they just did the right thing, in the interest of Territorians?” One woman asked.
Mr Barrett replied to the woman asking if she was “saying I did not act in the interest of Territorians?”
The woman replied that many people no longer trusted Mr Barrett’s judgement.