OK, since Sarge isn't getting it, I'll have a stab at it.
People have a right to do what they like, within the law. Human Rights Act says so (something Tories and Brexitiers are keen to repeal, btw, ask yourself why).
This right to do what they like, includes the taking of personal risk. So, I can go free climbing, pot holing, ski off piste, cycle down mountains, whatever. As a rule, though, I'm not allowed to put others at risk. So BASE jumping is still illegal, because if my chute doesn't save me, I might land on somebody else. For example.
So, people are free to smoke, if they insist. But what they are not free to do is put others at risk. So they can only smoke in places where others, eg non-smokers, won't be more than minimally affected.
There are also anti-discrimination laws, and general principles, so by and large you can't allow one person to do something and prevent another, and safety at work legislation, which you can't override by getting somebody to sign away their rights.
So, a smokers-only pub is a no-no, because it puts staff at risk, even if they are already smokers. What if they were to quit smoking, would they lose their job? That'd be discrimination, see above. And if they got cancer, or another smoking related disease, their employer might find it hard to argue that their working environment wasn't a contributory factor. Also, let's say the smoking pub has better beer, and a better vibe than the non smoking pub; I, as a non smoker might like to use it, but would be discriminated against if I wasn't allowed, and would be put at risk if I did use it. See above. So a smokers only pub is an unlawful and dumb idea.
The same isn't true for alcohol because I'm allowed to take personal risk, see above. What I'm not allowed to do is put others at risk by my action, see above. The collateral risks from alcohol are all secondary effects, eg violence and disorder. They can be dealt with under the law using other means, eg public order offences. You don't have to ban alcohol to deal with it.
What Sarge is complaining about is an apparent hypocrisy in banning one, but not the other. They are not equivalent, so it's not hypocrisy.
Vaping is new, and the law hasn't yet caught up. Under the principle of 'evidence based law making' I think governments would have to be satisfied that vaping didn't present a health risk, and I think evidence on that is still decades away, because it's too new.
