You've shown 1 example of an inexperienced cannabis user. Lets look at the direct, and some indirect consequences of other drug that are legal in the US. On average, 6 people die
every day from alcohol poisoning. In 2013, over 32,000
people died in car accidents. Tobacco is a factor in over 450k
deaths a year. In 2013, there were 16,000 deaths
from prescription painkillers. Even if you want to include indirect deaths such as your example, cannabis is far more benign than many other substances that are legal in the US.
The reason I'm starting with toxicity, is that I can state with a high degree of certainty that you can ingest as much cannabis as you want, and you'll still be here to talk about it in a few days. The same cannot be said for alcohol, oxycontin, or xanax. If the toxicity and risk from use of cannabis are so low, why do you feel a need to have it so restricted?
If there was a system in place to provide actual education around use and abuse, and a regulated market place, the cannabis related "deaths" would be expected to go down even further. I guess I think people should have the freedom to alter their mind and body in the way they see fit, assuming they aren't infringing on someone elses rights when they do it.
Don't you think it would be a better use of our collective time and money to go after the more dangerous drugs?