I think they do too, it's just a hard case to make. Many other categories of workers (including doctors) are allowed and encouraged to work until they drop from exhaustion; even many safety sensitive jobs have no formal rest/fatigue rules.

At SKW (and probably most regionals) the FA's usually get the same rest as pilots because they get the same schedules. They can (and occasionally do) require an FA to work beyond what would be legal for a pilot, but for the most part they stick with their pilots. Majors have more flexibility to run pilots and FA's on different schedules.