Not true, most of the ones I know are scheduled by the city 24 hours on 48 hours off.They work 8 hour (or 12hour) shifts like everyone else and they shift swap in order to get 24hr shifts.
Technically they arent supposed to sleep on the clock either.
So all the firemen, policemen, DR's, nurse's, are all suffering negative effects? No they adjust there schedule and lifestyle to fit their working hours. It would be detrimental if you had to do it one or two days a week.Nobody is saying the guys have a right to sleep on the job but its also unreasonable to make people work night shift 5 days a week for years on end. Its unnatural, unhealthy and has many negative effects on human beings. Will cracking down make them more productive or more miserable? No. So whats the point?