The same is true for Social Security. The boss allegedly pays half. In fact, the worker pays the entire 12.4%. If the health insurance and Social Security were shown accurately on the pay stub, the percent deducted would be much higher, possibly outraging the worker.
When one explains that, in absence of these deductions, the market would kick up wages, most folks deny it. If they make $15/hour now, they think they would still make the same even if insurance were removed. Insurance and half of SS are viewed as gifts from the boss.
The one making $15/hour is already making closer to $18 (?), but doesn't know it due to deductions-in-advance, These deductions are not in any paperwork that the employee sees.