Is it bad for an engine just to run on a cam designed for a supercharger w/o having a supercharged engine?

 

no, not bad; just not ideal

 

 

Not at all Most "blower cams" are simply cams growned on wider LSA like 112-114 along with more exhaust duration than intake duration.
Many fo Crane cams *street* "Off the shelf" performance grinds like the Powermax series are very Blower friendly and
work well on typical street motors N/A with mufflers and a full exhaust. ( dual pattern, wide LSA)

Cams like these tend to "drive" a lot nicer over all than racey tight LSA cams like ones ground on 106-108 LSA.
Especially throu closed exhaust with mufflers.

A "turbo cam" is a different story. Turbo cams have specific turbo friendly valve timing that neither suites a "blower motor" or a "N/A motor".

a nice example of a nice street blower cam as well as a nice N/A street performacne cam in the same grind is Crane cams
HMV-278-2

Works very well as a mild/ moderate blower cam and a mild/moderate street machine cam in a N/A motor.