Honestly, I fail to see why this should cause any more outrage than, say, an active duty service member being subjected to a search when they are on their way to be deployed
The child was treated in a professional manner, the TSA agent was explaining everything she did while she did it, and the search was no more rough or invasive than any other pat down I've seen. Obviously the parents didn't want her to go through the scanner, so that's what happens.
Shit, terrorists have NO problem handing a grenade to their child, pulling the pin and telling them to run up to the soldiers. Drug smugglers have NO problem telling children to swallow balloons filled with drugs. Just because a human being is under the age of 18 doesn't mean they cannot be a bomb or mule.
Bush started dismantling the bill of rights long before Obama came on the scene, you people gave up your right to unlawful search and seizure last decade and smiled while it happened.