What people don't understand is that all the seeming bullshit is there for a reason. The long zig-zagging line you have to walk through is so that cameras get shots of everybody at multiple angles. The slow pacing is so that there is time to run searches through databases implemented with 2001-era technology. You stand around for a few minutes between a wall of guards and a mass of people with your shoes and your belt off so if someone is identified they can't easily make a run for it. Bags and other items are placed onto a conveyor so that targets don't have access to their items when confronted. People are frequently pulled aside so that it doesn't freak everyone out when an actual target gets pulled aside.

Yeah, maybe if some idiot packs an AK47 in their carry on the TSA will catch them, but in general all the inspection is just theater. The TSA is there to stop previously identified individuals, who may be terrorists, or potentially criminals, or other "people of interest" from moving freely. They don't harass you because they're incompetent, they harass you because it is useful for their purposes to do so.