Tobacco may be the most* addictive delivery method, but nicotine alone is also addictive. To say its not is misinformation. Consistent use of nicotine still leads to upregulation, which does cause irritability, brain fog, cravings when you stop.

* I'd even change this to say modern nicotine salts in vapes are likely to lead to dependency faster than tobacco. A 5% nicotine salt pod will contain as much nicotine as a full pack of cigarettes, and so vapers tend to consume far more nicotine in a single sitting than they ever could with a cigarette. That combined withe constant availability means users of nicotine vapes & pouches (aka, no tobacco) are likey to have a more difficult time quitting than cigarette smokers.

Bottom line, its still dangerous to dismiss nicotine's addictive potential with or without tobacco as a delivery method.