You're right. You think it is all about the product so not much chance of having an intelligent discourse about the topic but I'll try to explain it just because.
Addiction is in the person, their chemical make-up and personality. An addict will find something to be addicted to. It is in their nature. Take gambling or sex or even chocolate. The addict doesn't crave sex or chocolate or a good poker hand. They crave the chemicals released by such stimuli. If they somehow manage to remove one stimulus from their life odds are they will seek to replace it with another that creates the same chemical release and reaction within their body.
Do you get it yet?
Partly true. Gambling can stimulate the dopamine receptors in the brain once it's conditioned to do so. Sex might be somewhat more addictive since the hormonal reactions caused by orgasm could further strengthen the stimulation of the dopamine receptors. Chocolate addiction might be comparable to gambling addiction.
However, opiods stimulated those receptors in a very direct manner. In the other examples above, the chemical comes from conditioning the brain to an activity (except that we add the chemical reaction of irgasm in the case of sex addiction). But in the case of opioids, no specific activity is required other than just finding any way to get it into the blood stream. The chemical is already in the drug and will stimulate the receptors on its own, giving a much stronger high than the weaker behavioural addictions.
I'm not denying that behavioural addictions can be very difficult to kick, especially if ingrained over many years. The the degree to which a person could get addicted to eating chocolate 10 years (if let's say is brain is conditioned to seek it out whenever he is depressed) is about the same as how much he could get addicted to heroin in a few days.
A person hooked on heroin over ten years will be incomparably more addicted to it than a chocolate addict will to chocolate over the same time period.
Yes, THC is far less addictive than nicotine, but still more addictive than chocolate.
Given the choice, I'd rather be addicted to chocolate since it would be a much easier addiction to break.