It's not unfair: it's preposterous. Around 99.999999% (give or take a few minute fractions of a percentage point) of passengers who have flown on US airplanes over the past few decades have not been looking to bring down the plane. Having to pay even one cent extra to be considered less of a criminal threat and to therefore receive better treatment by government employees goes against all notions of equality.

I could make up any arbitrary subset of passengers and deem them low-risk, because no member of the group has ever attacked a plane.

• Passengers named Fred
• Passengers born in 1962
• Passengers born at hospital xyz
• Passengers who attended a baseball game within the past week