We have a winner
From one of the articles you linked from the individual who got fired:
"Airline executives pressured the company's trainers to authorise the use of new, not fully qualified pilots, to cover the gaps, something Mr Sanit says he firmly resisted and which caused great unease among the trainers who were also pilots.
They were among those who refused to fly on Sunday, Mr Sanit said. Their distressed psychological state disqualified them from flying. Thus, Sunday's action was not a strike, not a protest, but was caused by a genuine problem within the company, he said."