Sadly would seem to be another chain leading up to the event.
Substandard Captain, according to his airline records, making a bad decision to depart. Extremely bad weather. Poor CRM with a very junior and inexperienced FO intimidated shortly before TO by the Captain. Mistakes in operational procedures. lack of piloting skills to correct the situation that then developed as a result. Neither possibly should have been in the seats they occupied
In fairness to the Capt under the prevailing circumstances he may well have been tense and worried. Who would not be with the prevailing weather conditions where apparently even the ATC were debating whether to allow him to depart. He already knowing that past performance had meant him being under airline scrutiny probably reluctant to disrupt the schedule.
Insufficient emphasis placed on basic handling skills in todays airline training environment. Although not a factor here the present situation where training organizations place new FO's with companies to 'gain time on type' leaving the Companies Captains to act as trainers is also a situation that seems unhealthy, automatics in after lift-off until time to land with little or no handling to avoid any chance of infringements. Would also seem to be loading the odds against the Captain should things go wrong with low time inexperienced FO's.
Under the circumstances here it is unlikely that the Capt based upon his purported history possessed much in the way of basic handling skills. The FO was unlikely to have had the time to learn much basic handling let alone in the type he was in. In the report though it does seem that he 'may' have had a better idea of what was going on and did attempt to give the Captain some feedback, as well as probably fighting for his life and attempting to do something rather than just sit there and go in.
Based on the reported situation the FO may well have been already flustered by his Captains attitude and previous behavior, and worried about extreme weather, leading to his not checking/initiating autopilot actuation.
Inability of either crew-member to see early enough that an unusual attitude was developing, or to correct the situation when it did, with both apparently applying opposing inputs when they did attempt to retrieve the situation. This has happened to more experienced crews in better conditions, Air India 747 rolling inverted at night, and some similar elements to the loss of control on the Gulf Air Airbus accident on the night overshoot at Baharain with a possibly substandard Capt and inexperienced FO.
Politics does sometimes play a role and may have here. The captain despite poor performance continued operating in command, the FO possibly without the experience/time to be where he was, the airline reluctant to fill gaps with expats. First route training Capt of mine in EAA was a Tanzanian and the best Dak training Capt I had the privilege of flying with. As someone has pointed out there are simply good pilots and bad pilots with everything in between.
This one sounds as though it may have been the wrong people in the wrong place at the wrong time for the wrong reasons.