It's anything but that,
Blue-Spheroid. From protecting children in cars, to workers in general employment to the specific possibilities and difficulties of employment in non-optional smoke environments, it can get very complicated.
But if we discard the OP's suggestion that we go back to free-for-all, and if we ignore the sidebar of kids in cars, then it really comes down to those hypothetical 'for smokers' establishments, and whether you can devise a law to allow such—and employees in them—that doesn't at the same time license if not outright encourage abuses elsewhere. Which is why the mere warning, "We're all a buncha, racist, faggot-hatting, sexist bigots here. Can't handle it, apply elsewhere model isn't good enough.
It's quite true that even with safety equipment, some jobs are inherently dangerous. Like farming. Hydro workers have way better safety records. Partly because of all that employer-provided gear, which self-employed farmers often skimp on. And it's also true that although Hyro workers don't give up their right to refuse unsafe work, they also don't get to suddenly 'discover' pole-climbing is unsafe after being hired. The deal is that they'll do the work and the employer will make it as safe as possible. That's why they don't do much pole climbing any more, and use bucket trucks instead.
To be a similar employment situation, the fume-filled smoke club would have to allow its staff frequent fresh air breaks and/or oxygen, supply appropriate masks or respirators, and install fume hoods over every seating position. Not impossible or even terribly expensive, and—as in the Hydro case—no guarantee of 100% safety, but a similar 'best efforts' recognition of the dangers the employer's asking the employees to face.
We long ago moved beyond the era of
The Jungle where any working conditions at all, no matter how unsafe, unsanitary or unhealthy could be imposed on workers because of their desperation for jobs. That's why we have all those health and safety laws that supposedly have made unions unecessary. And this one, that finally made workplaces smoke-free, after we suffered our deskmates' and shopmates' pollution for so long, is just another of those.
For them as wants to change it: Instead of ranting and whining, get serious and make realistic proposals that can give you your place to indulge your vice
without abusing others. So far this five page thread hasn't had a single such suggestion.
PS: I'm sorta surprised you stuck with the very-geared up Hydro workers as your analogy. Wouldn't trapeze artists and circus performers be better examples of folks who 'choose danger'? 'Course one imagines they get paid a bit better than the average wait-staff for doing so.
