To be fair, that this "scam" is still alive today is mostly by accident.
It stems from WWII times, when stateside laborers were uniquely low in supply and high in demand, and when labor had ridiculous bargaining power.
Laborers couldn't really ask for higher wages, because that was politically impossible (appearing to be extorting wartime needs for money was/is a faux pas).
So companies began competing on "benefits": health, accidental death and disability insurance among them.
To help ease the burden on employers and employees, the IRS allowed businesses to "temporarily" deduct insurance premiums. (This relief came against the backdrop of unprecedented wartime tax hikes).
Postwar, it was unfeasible to remove this measure, as the majority of Americans who had insurance got it through their employers: it would upset both businesses who have to pay more, and employees who lose insurance.
Later, some government (I forget which...) signed this stopgap measure into the tax code, making it permanent.
Regardless of the interesting history, I agree with you, it should be universally deductible.