The problem is you’re blaming the officers on the ground for the corporate policies in place.
As you yourself point out, security officers have managers like anyone else. If the manager comes down on an officer for not enforcing Policy X, they have two options - start enforcing Policy X, or start looking for a new job.
You also mention the difference between Corporate Policy and Law, but you don’t seem to understand how the two interact. In cases like this, apart from obvious racial discrimination and the like, the mall has complete freedom to dictate whom they allow in their establishment - it is private property, and legally speaking only those who have “permission” may be in the mall. Consequently, anyone the mall decides they do not want on their property for any reason at all, they have every legal right to tell to leave.
If those asked to leave do not do so, then Trespass Law comes into effect - if you are on private property without permission and are told to leave, you have to leave or you are legally guilty of trespass.
Now, is it fair that the mall doesn’t enforce their policies equitably? No, of course not.
But, sadly, it is their legal right as property owners to dictate absolutely who may and may not have access to their premises, and they can base that on whatever rationale or delusional insanity they please. Maybe they’re racist bigots. Maybe they’re conspiracy theorists who believe that wearing a purple shirt and khakis is the mark of the Illuminati. Maybe they go into a berserker rage at the sight of sweatervests. It doesn’t matter - if they want someone off their premises for any reason, they are legally empowered to ask them to leave.
Meanwhile, the security officer has no real say. They literally have one choice - enforce the absurd rule, or find another job. Most officers made to enforce this madness will just cringe a bit inside, swallow their pride, and as politely as possible go carry out their absurd duty. They just go and inform the poor people who fell victim to the mall’s stupidity and unfairness that they have to leave, and if they don’t comply then the police will be called to make them do so.
I understand your frustration. I understand this isn’t a fair, equitable, reasonable situation. But you’re trying to lay blame where it really isn’t deserved. The security officers don’t make the rules, and the vast majority of them would rather not have to follow such an obviously stupid policy.
If you want to fault someone, fault the mall. Boycott their establishment, hit them where it hurts - the wallet - and let them know that despite whatever legal rights they have, the customer is always right, and that their patrons will not stand for such inequitable treatment and absurd behavior, and are prepared to take their business elsewhere until such time as the offending policies are repealed.