While in the military and in my 28-year law enforcement career the phrase "sick, lame and lazy" was used countless times. It in reference to those who were not on the front lines or patrol duties, regardless of the reason.
Professionals who safeguard society will often "rib" others with the label or even give it to themselves if prevented from fulfilling the primary role of protector-warrior.
This may be difficult for those who have not served to understand the ways in which those who do interact. I think no apology was ever needed from Sheriff Adam Christianson. If the ex-deputy was truly hurt over this phrase, just imagine how devastated he must have been when cussed out by people on the street.