It wouldn't be for defending one's self. Management would find another path for it.
Listen, I wholeheartedly agree with you. However, just about any company will gladly dump an employee that stirs up controversy, even if that employee's actions were 100% correct. Given how passenger/airline relations are at the moment, I can't blame the pilot for trying to extract himself from the confrontation. Would I have done the same thing? Probably not. With my personal background, I'm more likely to revert to some of the self-defense training and mindset that I received working for a certain law enforcement agency. I would also expect my employer to terminate my employment for the "embarrassment" I caused them once the social media warriors launched their campaign. I would also expect to "cash in" on my investment in union membership as well.
If a job with an employer that would place such little value on your physical safety as an employee, is more important than your life or the suffering of serious bodily harm that may well prevent you from keeping that job anyway; then by all means, stand there and take a beating for them.