The Transportation Security Administration (TSA) is an agency of the U.S. Department of Homeland Security, which has authority for the security of such, for those traveling from one destination to another that involves the United States homeland, and in particular, are common to see at virtually any major airport within America, though, surprisingly, there are some notable exceptions, such as the San Francisco airport, in which private screeners are used instead, though, such screening and permission are actually granted under the aegis of Homeland Security.
There probably aren't many passengers that are happy to go through the inconvenience and sometimes the embarrassment of TSA screening, whichmay involved invasive pat downs, the necessity to take off or out one's belts, wallets, shoes, and so forth, the removal of laptops and other assorted items from one's baggage, with some unfortunate souls having to endure even more intensive private screening away from other passengers, as well as the annoyance and the confiscation of certain personal items violating rather arbitrary approved carry-on items, in addition to the time wastage and long lines which can result in a missed flight, or lacking proper identification which can do the same, to the actual denial of admission to your flight, are all part of the comprehensive TSA process. For the millions of passengers that fly each year, few are appreciative of the consideration and courtesy by TSA officers, rather, many see them as bureaucratic flunkies, that are incapable of assessing the situation right to begin with, and make mountains out of molehills, and are arbitrary, creepy, and sometimes corrupt.
Though, many people do express the need for some sort of airplane security, so as to avert any other future airline terrorist events, the precision and professionalism needed to conduct such in a thorough but efficient manner, seems to not be in the TSA playbook. However, the TSA, came to the decision or had the decision made for them, that if instead of treating all passengers as potential criminals, if they instead divided passengers into the privileged class and left all others as potential criminals, that their effective approval rating by the people that really matter would increase considerably, for while America speaks loudly about equality and fairness, it doesn't actually practice it. So that, for those that have $85 to pay for TSA pre-check, and are willing to provide their respective identifying information as well as to show up at a satellite office to be fingerprinted, if they are thereby approved, they are now accorded their own TSA pre-check line, in which, they won't have to worry about suffering through an enhanced pat-down, or the inconvenience of taking off certain items of clothing or unpacking certain things from their carry-on, but will typically be treated more with "kids' gloves" and therefore glide through security through a shorter line and probably a more considerate attitude by the TSA crew.
This means, for those that hardly travel at all, or don't wish to devote $85 to TSA pre-check, or know that because of a previous arrest, conviction, or something else, that they aren't model citizens, that they are effectively forever placed in the category of "those that need to be watched", whereas those that have money, or their company pays the fee for them, or are boring, obedient, or even good citizens, don't have to go though the inconvenience and indignity of the TSA pat down, signifying that when it comes to travel in America, that there are two basic classes, those that are treated with respect, and those that are treated with contempt. So that in America, it is only too obvious, certain oppressive rules apply only to those other people, and never to those that are favored or coddled by administration policies.