This is difficult, and I can easily envision my mother in such incidents. Looking at this from the point-of-view of the victim, the TSA clerk and a bystander:

Exbayern's point (I think) is that the victim is already embarrassed enough without drawing added attention to it. I can't imagine my mother shouting "she's trying to see my diaper!" or "I needed the restroom so bad I wet myself!" or "she's pushing on the scars in my breast" nor would I expect her to. Most people would be hesitant to expose such details, and even in lesser situations, many people would rather "suffer through" than make a scene. I know from experience how quickly things can go from the point of "please don't make a fuss over me" to being unconscious! And infrequent travelers are caught by surprise that a gov't "agent" would be so insensitive. We can't expect that everyone will stand up for themselves in such a situation.

Unfortunately, I think TSA employees (possibly unconsciously) often take advantage of this. I sense an attitude of "I know this embarrasses you, but you won't complain out loud because that would be even more embarrassing." It's been said that they need training to be more sensitive (in their words as well as literally in their touch) but given the "we are the front line, you are a potential terrorist, you will RESPECT me" attitude, I don't see it happening across the board.

Then there's the role of the other passengers, which is Saitek's point. And while I agree that anyone should jump in if there's actual violence or if the victim is shouting for help, LeeAnn's mother was quiet until the screener started screaming at her and quiet throughout her second incident (OP). If it were my mother, I'd (try to) intervene as soon as something looked wrong. But for a complete stranger, it's hard to judge exactly when it's gone too far. If someone is starting to cry, or shake, or seems under verbal attack, is it better to try to help, or will you just add to their distress? Should I, as a woman, go to the aid of a man 15 years younger, or will he be offended and further humiliated? It's hard to assess.

These are not easy questions but I agree that we all need to stand up for ourselves, and for each other, a lot more!