Panic attacks are a silent problem. Unless you have to speak in public, you're probably the only one who knows you're having one.
Colostomy bags are a private problem.
Insulin pumps are a private problem.
If people actually made a fuss every time their privacy was invaded - if every single person whose private medical problem was invaded by the TSA or whose body was touched in an unseemly fashion were to weep out loud - many more people would notice.
What's happening is a conspiracy of silence. Between the desire to get it over with, embarrassment, fear, machismo, cowing to authority, calculating your odds of a successful protests (zero), whatever the operating mechanism is, most people who are invaded do not voice their discomfort.
As for the onlookers, there's the discomfort of seeing someone else assaulted, the natural instinct being to avert your eyes when something embarrassing happens to someone else. There's wanting to make your own flight and fear of retaliation if you try to intervene. Add to that the fact that many won't believe that this stuff happens or are deluded to believe it serves some greater good. At the end of the day, we remain silent IRL, and let the TSA travesty go on.
This internet forum is one of the few places we can talk about it.