I can appreciate the sentiment, but the only reason labels are put on anything is strictly for liability issues and nothing more.
Tobacco companies would never have printed warning labels if it didn't become mandated. When you were a smoker did you ever read the warning label and think "I'm never going near these again" and just up and quit? Anyone who is, or was a smoker knows good and well that their ingesting poisons, toxins, carcinogens and a slew of hundreds of industrial chemicals used to increase the potency of cigarettes. Usually it's when you start to feel the wear and tear on your body that you finally decide to do something and quit, but I doubt warning labels have rarely done a whole lot to deter longterm PAD smokers from just up and quitting on the spot. So how is that warning label going to be more effective for a child than a fully grown adult who knows that label is right there in front of them while they continue to smoke?
It simply comes down to the manufacturer avoiding a lawsuit.
And although I don't like vaping being compared to gun ownership either, it still is a valid point. There are any number of life threatening products people keep in their homes, and it is specifically the owner's responsibility to keep those items out of harms way. If your child did ingest any number of household cleaners or prescription drugs and you filed a lawsuit, the manufacturer is protected by that label in court, NOT you or your children.
That being said, if it bothers you that much, than you should buy your liquids from manufacturers who do label them ... Totally Wicked, Johnson Creek, Mad Murdock are a few...