You could substitute any number of employers in there, it's not just the TSA that's despised. Tax collectors, politicians, financial analysts that nearly bring down the US economy, traffic cops, the list goes on.
I don't concern myself too much with empathizing with TSA employees, it seems like an odd thing to do. There are more important things to worry about in this world.
There's one difference with many of these examples: unlike experiencing a mean TSA officer going through security you can get someone to help you (family member, attorney), or request another representative. If you don't like your pat-down officer at the airport you would have extreme difficulty in requesting another persons assists you.
One of the reasons we hate the TSA so much is that you lose all control between the gates. If things go badly for you you must comply regardless or face genuine time-sensitive consequences.
I don't concern myself too much with empathizing with TSA employees, it seems like an odd thing to do. There are more important things to worry about in this world.