Uninformed does not necessarily mean stupid. Besides that, where would you draw the line? Can't this argument be made more or less for every safety-feature ever? Why dictate seatbelts when you can just drive safely and not be stupid. Why have protective equipment etc?
Nobody who buys a portable generator is uninformed about the required safety precautions. They're stated explicitly in the user manual.
> Can't this argument be made more or less for every safety-feature ever?
Yes. And the answer is the same for all of them. The fact that in our current society, many such regulations are already in place, does not make those regulations good ideas. It just means our society is not a sane society. Which should be obvious to anyone paying attention anyway.
Not everyone using a generator in a crisis bought the generator. Not everyone where a generator is being used in a crisis even speak the same language.