Because when things go bad in the cockpit, the lives of the two pilots, nine cabin crew, and the one-hundred and seventy or so passengers ALL hang in the balance. And unfortunately in some cases, no-one gets to go home because the bodies cannot be identified in the wreckage.
I would hope that when things go bad in the cockpit things aren't hanging in the balance. Training, currency, SOPs and safety management are all mechanisms to ensure that this isn't the case are they not?
Obviously the argument of being 'life and death' decision-makers is not washing it with the public and employers at large. There is a general perception that flying is among the safer forms of travel and yet passengers seem not to be aware they are perilously close to the precipice according the description above.
Although I don't agree with flying/medical/legal professional comparisons anyway, I think that the idea that a surgeon is somehow absolved of the burden of responsibility that pilots must bear because
he still gets to go home and reflect on it
is fatuous. A surgeon has to live with his mistakes, a lot of pilots do not. Which is harder?