I strongly agree, cannabis can have really unpleasant side effects, and it can be unpredictable and volatile. It does differ from coffee and even alcohol in this regard, though in a varying way.

Start with coffee. Coffee isn't dangerous from a fatal overdose perspective. It would take ~80+cups of coffee in a very short amount of time to reach life threatening caffeine levels. Something other than the caffeine would threaten your safety before the caffeine did. You can drink enough coffee to have a very unpleasant experience (I certainly have), but it's not a confusing substance, and most people know their limits (1-2 cups every few hours at most), and it's easy to stay within these limits. Different brews can definitely spike the coffee level, and I've had a few moments where I had just one (admittedly large) serving of a high caffeine grind and found myself more wired than I wanted to be.

Now, that said, if you eat three spoonfuls of caffeine powder rapidly, different story. That is quite rare in the caffeine world, though, and most people wouldn't consume the drug this way (it would in fact be rare, though caffeine pills might do it?).

Moving on to alcohol. It actually is quite dangerous from a fatal overdose perspective, mainly because many people enjoy (at least short term) getting quite drunk. It's generally easy to find alcohol in mild, easily understood doses, with some risks - "IPA" beers can surprise people who are accustomed to drinking pilsners. However, alcohol is regularly served and available in high concentrations that can be rapidly consumed before the effects set in. Coffee is easier to regulate, people don't generally enjoy getting too wired, and has an incredibly high fatal overdose threshold. Alcohol, on the other hand, is a substance that people usually consume like coffee (a couple pilsners, or glasses of wine), but there is a common use case where people deliberately drink a lot on purpose, and the delta between very drunk and fatal overdose on alcohol is much, much narrower than very wired and fatal dose on caffeine.

Now on to cannabis. Cannabis almost only exists in something similar to that highly volatile, powdered form of caffeine, and unlike whiskey vs pilsener, it is not apparent what you're consuming. Weed ranges from 1%THC to 35%+. If it is smoked, the effect at least comes on relatively quickly, but there's a long enough time lag that people can unintentionally take up to 100 times the dose they intended to. If you eat extracted THC, the risks amplify even more.

Another interesting thing about cannabis is that it appears that high doses, you get an unusual effect - the opposite of what people experience at low doses. For some people, if you drink a little caffeine, you get a little wired, if you drink too much, you get too wired. Same for getting drunk with alcohol - high doses have a similar effect, but to an undesirable magnitude. Weed, for some people has a different effect - take a little, get a little relaxed. But if you take too much, you don't get too relaxed, you experience the opposite, extreme anxiety and paranoia.

One saving grace of cannabis - unlike alcohol, the delta between being way, way too high and dying of an overdose is massive. In short, the danger of an unpleasant episode of cannabis is the unpleasant episode (well, there may be long term psychological effects).

My opinion is that cannabis should be legal, and that the practice of putting the potency on the label from a proper lab is a huge improvement over what we had before (some dude on Haight street reassuring you "nah, dude, this is the chillest, the chillest bud"). I also suspect that people who experienced heavy paranoia might not have been on the very low doses though thought they were (we're talking about 1.5-3% vs 30%+). Some people claim that CBD reduces the risk of anxiety, though others think that this is just a result of lower THC levels among high CBD stains.

Anyway, that was a very long passage of agreeing with you. It's hard to take a "small" dose of cannabis, it's hard to know to potency of what you're taking, you're "all in" before you find out, and the effect of large doses can be the opposite of small doses. There may be long term effects, certainly of excessive use at high doses, but the odds of a fatal overdoes, on the other hand, are vanishingly low.