Why would Air France fly to Algeria when it had a civil war? I was reading about the Polaris Award that was awarded to the pilots of Air France Flight 8969:


  Algeria was in a state of civil war at the time of the hijacking. Aircraft flying to Algiers faced the possibility of missile attacks. As a result, Air France's flights to Algiers had crews entirely made of people who volunteered for the route. Air France had asked government officials if it absolutely had to continue flying to Algeria; as of the time of the hijacking, but they never gave Air France a reply. Bernard Delhemme was the captain of the flight.[3] Jean-Paul Borderie was the copilot, and Alain Bossuat was the flight engineer.[1] The Airbus A300B2-1C, tail number F-GBEC, had first flown on 28 February 1980.[4]



Please see the question in the title.
Why would rational air crew volunteer to fly to a state with civil war, like Algeria? Did they have optimism bias? How did they underestimate the risk?
A civil war yes, but it still had a government and this was supported by France.
A flag carrier like Air France does not really have all that much leeway in terms of what they can do and it was probably in the nation's interest to show support to the legal government. Since they had asked, the answer was probably yes they had to fly(but no politician worth his salt would be on record as stating that! Without an airlink to the outside world a lot of things would come to a halt. I would imagine a lot of people who were trying to assist in finding a conclusion (mediators) would be users of the flight. There would also be a steady stream of people leaving the country and AF may be one of the few options available.
Most airlines treat flights into danger-area differently and where unions are strong having volunteers to operate the flight may be an acceptable solution to both the airline and the union.