He made a mistake that cost a whole plane load of people their lives. He deserves to be fired from Comair. People are fired everyday from other airlines for damaging aircraft or putting people in danger. He helped total one and kill people. If he wants to apply to another company with an accident on his record, more power to him.
People are fired for showing up to work drunk, that is certainly poor judgement. We are paid to make difficult decisions and decipher charts and procedures, he failed at doing his job and subsequently a bunch of people died.
I am not saying it couldn't have been me, but if it was I would understand what the implications were