It's important to note that the authors literally are assuming a cause of death here because they ruled out many other common causes. There is no direct evidence in these two cases that the cannabis they consumed actually was causally related to the fatalities. There are not witnesses who say yes, he was fine, then he smoked pot, then he had a heart attack and died.

The authors conclude with After exclusion of other causes of death we assume that the young men died from cardiovascular complications evoked by smoking cannabis. Given that the authors admit that hundreds of millions of people smoke cannabis every year, some will likely die within a day of having smoked it. Does ruling out known causes of death and confirming THC in blood create a strong argument that the cannabis they smoked is to blame?

This piece winds up being a political flag in the sand in the form of a not-terribly-well reviewed medical case report article. The case reports are fine, but assuming cannabis involvement seems like it should take more given the long history of inability to confirm causal links to fatalities.

The two cases had THC levels in femoral blood of 5.2ng/mL and 1.9ng/mL. Both of these are low levels, so it had probably been some time since the decedents smoked. The authors do not mention any witnesses or any other details that help link cannabis to the deaths other than the fact that the two people had died and had probably smoked cannabis within 2-10 hours of dying. See Desrosiers NA et al. 2014) for more about THC levels in blood.

It seems very likely someone can die causally from smoking cannabis, but this article does not move the data forward very far. :\