Not Terrorism Not SUICIDE
There has been a contradiction on the mental make up of the FO by the prosecutor who has also dispelled suicide.
A lot of posts have referred to the young pilot poor employment and conditions driving him to take his life and everyone else.
The fact that the prosecutor has dispelled suicide isn't as stupid as it sounds
The prosecutor discussed that when they got to the landing briefing the FO became very kurt in his responses.
There are certain people who have anger management problems and cannot take criticism. On the surface they appear friendly until something triggers that anger and then they see Red, the anger becomes uncontrollable and they have to vent that anger on something or somebody.
Blind rage! and i stress the word BLIND
It is more likely seeing the prosecutors comments re suicide that the Captain triggered something in the FOs mind where he lost the plot.
He probably didn't even consider his own imminent death or the PAX but satisfying his rage against the Captain by crashing the aircraft.
Don't presume its some poor lad with lifes woes on his shoulders trying to kill himself this is something else and probably goes way back into his childhood