And based on my own (admittedly, limited) experience, I stick by my belief that you are completely wrong is your assessment of TSA personnel.
However, statistically, if MOST TSA agents were as awful as you think they are, I - as a grumpy, demanding, semi-paranoid, bitter, jaded, pessimistic old cynic - should have encountered at least ONE such awful agent since TSA was established 7 or so years ago. Yet, inexplicably, I have not. Not one.
Although I have met a few who were clearly not ecstatic in their jobs, I have yet to meet one who treated me or anyone else around me poorly, violated ANY TSA or FAA rules, regs, guidelines, or Federal laws, or even came close to fitting your description of the dregs of humanity that you seem to think are the most common type of TSA agent.
I usually fly out of DFW and believe me the TSA agents at DFW are at best just hostile toward the flying public. I have yet to see one smile and God forbid you say good morning to one. Last year, my husband simply said, "good morning, how are you doing?" when one glared and snarled at him and said, "what's good about it? I'm not here to chit chat, put you bag on the belt". My husband's carry on was already on it's way through the scanner by that time, by the way.
I posted on here last year about a TSA incident that left everyone around me livid. They had the little glass booth thingy set up where the door opens, you step in, wait, they blow a puff of air at you to check for explosive residue, then another set of doors open, and you step out the other side. This was after you had already gone through the metal detector. Anyway, a few people ahead of me there was a young couple with a little boy about 3 y/o. The little boy was terrified of the glass box and didn't want to go in it by himself. They refused to let either parent carry him in. The dad walked through to show him there was nothing to be afraid of, but the little boy clung to his mother in terror. She begged the TSA agents to let him go in with her, but they refused, insisting he had to go in by himself. The mother tried her best to calm the kid down and to get him to walk in, but he was having none of it. The female TSA agent literally yelled at her, "get him in there and get him in there now!". This little boy had already walked through the metal detector by himself. He wasn't happy but his parents had apparently prepared him for it and he did it. The glass box was just too much for him though. When the little boy wouldn't let go of his mother, the TSA agent literally grabbed him out of the mother's arms and pushed him into the glass cubicle and when the door shut, the little boy started beating on the glass door, screaming and crying at the top of his lungs trying to get out. That was bad enough, but all the TSA agents standing around started laughing hysterically at him. Everyone standing in line waiting was furious and several started asking the TSA agent if it made them feel big and tough to terrorize a 3 y/o.

Sept 26th I was flying out of DFW to MCO. I was doing carry on only. In a packing cube I had a quart bag full of bath salts. They were labeled as such. For some reason the TSA was fascinated with them. As they went through the scanner, the agent called someone over to look at them. As they came out of the scanner the second agent asked whose bag it was and told me he needed to search it. He opened the quart bag, smelled of them, ran his gloved fingers through them, took some out running them through his fingers, ran a cloth over them to check them, and then just held the bag for awhile looking at them with a very confused expression on his face as if he didn't know what to do with them. I felt like saying, "excuse me they are solid, not liquid and are labeled."

