They changed how they make chewing tobacco (aka moist snuff) about 20 years ago and it has less of the cancer causing stuff (Nitrosamines) in it, its now closer chemically to snus - I’ll point out that Scandinavian countries have some of the highest use of oral tobacco in the world, yet last I looked some of the lowest incidences of oral cancer per capita.
The function of if tobacco causes cancer has as much to do with processing (it used to be cured by wood fire at a higher temperature which is where much of the carcinogenic properties came from) and the byproducts that processing creates, particularly Nitrosamine, its now cured differently in a process which is closer to snus, and somewhat safer.
Nicotine addiction (which I have) should be about harm reduction first, cigarettes are the only product that I can think of if used as commonly used will kill you or dramatically shorten your life, and it probably wont be cancer, it’ll be COPD, heart disease, or other cardiovascular issues - which are the same issues firefighters get from repeated smoke exposure. Breathing the byproducts of combustion is what’s really awful (and deadly).
It's a serious concern and switching to synthetic nicotine products may prolong your life. All tobacco products are highly carcinogenic. Contrary to what was said earlier it is not really about the smoking (though of course that makes things worse).
Nicotine products aren't safe; they are highly addictive and may exacerbate tumors that are already there. But they're far less addictive than tobacco products and they probably won't kill you.
I agree with you that tobacco is uniquely harmful, but smoking by itself is also bad by itself. Even exposure to smoke from campfires, if chronic, will elevate your risk for COPD, cardiovascular disease, lung cancer, etc.
Smoking/smoke inhalation is not safe, it leads to all the bad outcomes you mention, and I encourage everyone to seek out alternatives like oral nicotine pouches and cannabis gummies. They will almost certainly improve your healthspan and may well improve your lifespan. I personally stopped smoking because my wife told me she wanted me around longer. I am all aboard the "smoking is bad for you" train.
But the role of the smoke itself is overemphasized which leads to a false sense of security. Switching from cigarettes to dip does lead to a significant improvement in mortality. But the real step change is moving to oral nicotine pouches, gum, patches, etc.
I'd also point out the risk from campfires and from cigarettes is not at all comparable. They are several orders of magnitude apart. Even smoking marijuana isn't nearly as dangerous as smoking tobacco. (Smoking marijuana is not safe, that just goes to show how ridiculously dangerous cigarettes are.)
Becoming addicted to a substance is harm, so being addictive is a risk.
Nicotine is not harmless. It is a teratogen, it may exacerbate cancers you already have, it can harm brain development in young users, it can cause high blood pressure, etc. And as stated previously - it is not good to be addicted to something! That is a bad health outcome in and of itself!
I occasionally use synthetic nicotine products, I don't judge people for using them, but let's not misrepresent what this is. It is a drug. If you take a look at the risks and decide it's worth it more power to you. But don't tell people it's harmless, that is dangerous misinformation.
I don’t think this really holds up, for example helium itself is chemically inert and not toxic. The main risk from inhaling helium is probably oxygen displacement at a push.
Millions of people have been using inhalers to control asthma too, this well studied and agreed to be safe. This is just off the top of my head.
The HN guidelines say "Please respond to the strongest plausible interpretation of what someone says". The way I understand it is that different people on the thread often have different ways of thinking about the topic, and we shouldn't dismiss something because it's not what "we" were talking about. In this case, it was obvious to you that the parent was talking about smoking tobacco, right? So you can either engage with it, or not, but there's no need to reject someone's comment for not adhering to what you decided is the topic.
Who's trying to avoid talking about tobacco? TFA is titled "Scientists solve 200-year-old puzzle of how tobacco plants make nicotine", and my sense is that the thread is very much about which of the effects of smoking are explained by nicotine, and which are better explained by other factors of smoking tobacco.