I think the parent means that it's a career choice that in the US is quite well payed especially after some tenure, given the level of training /education required. It also comes with a ton of job protection that's rare in the US, and a pension. Couple all of that with a monopoly on violence in society, and police in the US occupy a position of unusual privilege.

It's a luxury, not a service. If we're just making blanket statements without explanation, we can invert them.