For all we know the uninjured pilot was not the instigator
But he was injured according to the press report. He was allowed to fly after the company's 'safety director' checked him out. I wonder if the safety director is a doctor? Loads of fights have ended with no apparent severe injury. And then one of the pugilists later keels over with a bleed on the brain. It doesn't happen all the time, but it happens. Also, I imagine the adrenalin rush that occurs during and after a punch up doesn't exactly make for a conducive mental condition for work.
Whether or not you want it, you pilots are held in great esteem by the vast majority of the public. I think they would prefer to fly without a crew member that hadn't just been involved in a brawl.
Like
button push ignored the Korean cargo crash at STN also sprang to my mind when I read about this. IIRC the RHS just kept his mouth shut even although he knew his inaction would kill them all, the military thinking was that pervasive.
I too am sure there was a case (in the 80s) where the flight deck were fighting with each other before crashing, but a quick search reveals nowt.