Except the firefighting job isn't a punishment of a crime. They are volunteering for this job, no one is making them do it.
If that’s true, does it extend out past sexual activities through to workplace choices? Do they actually have a choice, do they actually consent? What’s the difference? Where’s the line?
I'd guess if one didn't want to do it, he/she could just slack off and not join.
Look it up and watch the show if you can.