The whole reason sick days are a thing is that giving employees paid sick time costs you less when they don’t come in and make other employees sick. If enough people get sick in a given org, that has a way of really impacting everything about a workplace, it really is cheaper if they stay home until they’re not contagious.
The worst part of this situation, to me: that anyone is pressing for sick leave to be tightly audited, or seeking to frame its use as a sort of graft or taking from the employer, or a pretext for preemptively firing employees deemed guilty of being too sick. This kind of talk creates pressure for employees to come to work sick in order to avoid being seen as slackers or thieves, and that in turn (especially in an environment full of flu and covid variants, doubly so on the heels of a fucking pandemic so we should all know better by now) defeats the point of having sick days in the first place.