Sorry, but you're making the same logical error of assuming that A implies B means B implies A. Let me help you understand:
> It's not that A implies B. It's that B [did you mean A?] is contained within B.
"A implies B" and "A is contained within B" are equivalent statements. For example, if you are Catholic, you are a Christian. Being Catholic implies being Christian. Catholicism is contained within Christianity. However, you can't go the other way. Being a Christian doesn't imply that you are a Catholic.
Regarding alcohol consumption, we talk about about consumption, compared to beer consumption, because we know that alcohol consumption has the same general risk profile whether or not you're drinking beer, wine, or spirits. The important part is that alcohol has been shown to have negative effects. Because alcohol has been shown to have negative effects, we can extrapolate that beer has the negative effects associated with alcohol, However, if only beer had been shown to have negative effects, we couldn't automatically assume alcohol was the cause because there is a lot of other stuff in beer that distinguishes it from wine and spirits.
Now the same thing applies to smoking. Smoking is known to produce over 9000 chemical compounds, 70 of which are known to cause cancer. At least part of the causal link to cancer is specifically tied to the compounds from combustion specific to smoking. Therefore, we can't automatically assume that nicotine is harmful just because its present in smoke and we know smoke to cause cancer.
Here is an overview from Cancer Research UK: https://www.cancerresearchuk.org/about-cancer/causes-of-canc...
> Nicotine is the chemical that makes cigarettes addictive. But it is not responsible for the harmful effects of smoking. Nicotine does not cause cancer, and people have used nicotine replacement therapy safely for many years. Nicotine replacement therapy (NRT) is safe enough to be prescribed by doctors.
So, in short, just because smoking is known to cause cancer, doesn't mean you can assume that nicotine would be responsible for the same number of deaths if you replaced smoking with some other form of nicotine consumption.