TSA are just cops, and all cops are bastards.
But even if we ignore systemic issues with policing under capitalism, the fact remains that no, the job doesn’t have to be done, as evidenced by the fact that TSA fails penetration tests 90-95% of the time. They literally do not do the thing they were put in place to do, and nothing happens because of it. Terrorist attacks on planes are incredibly rare, and TSA does nothing to prevent them anyways. It’s all just theater to normalize law enforcement overreach.
Fascism is a social disease that is injected by the bourgeoisie into the petit-bourgeoisie during times when capitalism is in crisis. They do this through propaganda and economic warfare like austerity coupled with tax cuts for the rich. This results in an economic downturn that hits the “middle class” the hardest (relatively - poor people are also fucked, but they had less to lose in the first place). Economic woes coupled with divisive and authoritarian propaganda and — boom — fascism.
So how do you stop it? Well, ultimately by dismantling capitalism and removing the power of the bourgeoisie. Otherwise fascist crises will just keep being manufactured.