Society has evolved to the point where many people are regularly traveling long distances. Flying itself has become an integral part of this travel, to the point that driving or taking the train across the country is seen as adventurous. Flight transport is a commodity provided by many carriers in a mature market. The economics of and reliance on this market may change in the future, but as it stands, this commodity is relied upon by the modern world.

To say that carriers should be able to selectively revoke this abstraction and deny travel to specific individuals is to give them the power to force arbitrary rules on anyone who relies on this infrastructure. This would make all rights subject to the whims of the airlines.