In general, security arrangements involve a transaction of unquestioning obedience to authority in exchange for preferential treatment, which can then be leveraged by the authority holder to pursue illegitimate ends, eg doing things that are outside the legal scope of managers (in the private sector) or elected officials (in the public). Because security personnel are delegated enforcement authority, instant challenges to them are treated as breaches of security; challenges can only be made administratively, even though the act of enforcement can change the fact situation sufficiently to render the administrative challenge impossible or moot (ie people give up because pursuing the administrative route is often not worth the trouble).
The security officer's dilemma is that doing their job requires them to not think very much about what they are asked to do. If they begin to have thoughts of their own about what is ethical or not and decline to assist an authority figure who asks them to do something unethical, then they risk loss of their security status and are suddenly treated as a security problem themselves. It's int he interest of authority figures to excuse and cover for minor lapses of security officer behavior so that when the authority figure wants something illegitimate, they have leverage over their security apparatus. Overly scrupulous security personnel don't get promoted.
It's worth considering that a high portion of our economy is based on the use of guard labor (not including regular law enforcement) and that this may have or perpetuate distorting economic effects: https://www.brown.edu/Departments/Economics/Faculty/Glenn_Lo...