It seems that a lot of people have the impression that security is an invasion of privacy. It can be. But it is not always an invasion of privacy. If you go into an airport and you know that there is a lot of security there then it is not necessarily an invasion of privacy. Invasion of privacy is when police search your house without having a justified reason with a warrant to search your house. Now consider airports. No one is making you go into an airport. If you go into an airport you agree with their security standards and so it is not an invasion of privacy.
I do not believe in TSA. Safety is good, but TSA puts safety on steroids. Safety should not be the only thing you focus on. Here is an simple example. Suppose there was a law requiring all drivers to also wear helmets in addition to seat belts, and laws that banned motorcycles. Would such a law save lives? Absolutely. But I doubt many people support such crazy safety standards.
I also believe that safety should be managed by the airports themselves. This creates many different competing models for safety. Some which may be more hardcore on safety, and others which are easy on safety. I do also believe that this opens up room for more danger, but so what, there is a point to how crazy safety can get.
As Penn Jillette said in a Bullshit episode on gun control, "you cannot stop insane people from doing insane things by passing insane laws, that is insane". I see TSA as taking safety too far and so I do not support it.
Furthermore, the TSA is an invasion of privacy. Because it mandates all airports to use the same security system. If airports were able to choose their own security system and people would be able to choose what security system that they wanted to adopt, then this would end the violation of privacy. But if you have a single uniform mandate on every single airport and people have no other option when they want to leave or enter the country to go through a different checkpoint then that is an invasion of privacy.