Your example is a false equivalence. Economics does not define "good ideas" and "bad ideas," it only attempts to model resource dynamics. Whereas the spread of infectious disease is clearly quantifiable regardless of value assignment.
Partly true, but besides the point. Making a blanket statement like "economics says rent control is bad," is only marginally better than saying "physics says nuclear weapons are bad." There is a critical assumption of values which is totally outside the objective of study.
The presumed goal of rent control is to prevent rents from rising. If they actually cause rents to rise even more quickly then they are indeed "bad" (at achieving this goal).
The goal of rent control, as I infer from the mechanism, is to prevent existing tenants from being priced out of their current homes (eventually leading to eviction) - at least as I have seen in the US.
If the goal were to prevent rents from rising, the mechanism would do so directly, ie. regulate all rent, rather than limiting to continued rentals on certain types of property. Which would by definition prevent rents from rising, presumably along with other undesirable effects.
Anyways, the whole issue with conflating "bad" with objective consequences is the "presumed goal," which is of course totally subjective.
