By any reasonable assesment what he did carried no risk . . . . but, he bust the rules and knew he was doing so (no matter whose idea he now says it was)
In another airline that Slim is familiar with, we not so long ago had a Capt demoted for several months and a contract F/O dismissed (not even required really, just not renewed/rostered is enough ) although he was sensibly IMHO reinstated.
This was for a similar "incident"
I believe this was probably a more measured response from a company many on here would be quick to criticise for their "personnel handling".
In Capt Masson's case I have the distinct feeling that they wanted rid of the guy anyhow, and he handed them the excuse they needed on a plate.
Shot himself in the foot, unfortunately for him.
Case dismissed I would hazard.