"Protected status" is a bit of a misnomer ask any Human Resource person who's been at the end of a discrimination lawsuit.
The law has been read to mean any person of persons who can demonstrate an arbitrary, capricious or inconsistent prejudice or harm based on ANY characteristic is on a "protected status".
I think you're conflating constitutional Equal Protection with statutory anti-discrimination law.
Constitutionally, EP has specific requirements where the level of "scrutiny" the court will apply to a challenged law is wedded to the the plaintiff "protected" status. E.g., a law would probably be unconstitutional under EP if it classified people based on race, whereas it would probably not be unconstitutional if it classified people based on educational level.
In the Constitutional EP context, arbitrary, capricious, or inconsistent lawmaking is theoretically okay, provided that the government can show a legitimate purpose and that the law is rationally related to that purpose. As was famously said in dissent to an EP case (whose name escapes me at the moment), there is nothing unconstitutional about a silly law--as long as the court can conceive of a rational basis for it.
That said, statutory anti-discrimination law, such as Title VII, has completely different requirements. When discussing discrimination lawsuits in the HR context, you are almost certainly dealing with statutory law--not with EP. These statutory requirements are quite different than Equal Protection under the 14th Amendment of the Constitution.
Since I don't know a lot about anti-discrimination law, I will leave that topic to another poster. But if I were a betting man, I would bet that statutory anti-discrimination law would not get you very far with a LEO/non-LEO classificaiton; most of these statutes are tied to characteristics such as race, age, national origin, sexual orientation, etc--but not LE experience or lack thereof.