They are both fairly benign chemical compounds, formed from precursors that are somewhat dangerous. That's the only "similarity" I was trying to demonstrate. An overdose of NaCl will kill you just as dead as an overdose of MDMA will. NaCl solutions used to be used to induce abortions, and an IV solution of potassium chloride (a very similar chemical) is used to stop the victim's heart during an execution by lethal injection. Of course, these examples are not "normal usage situations". Nobody dies from ordinary use of NaCl. Can you point to any cases of a healthy individual who died from a normal dose of MDMA? Not adulterated pills, whopping overdoses, or mixing it with other drugs. Pure MDMA.
KCl is also what Dr. Kevorkian uses in assisted suicides. It is also in Gatorade... To further illustrate the point, I see people everyday who are very sick, and dying, because of NaCl. Hypertension and stroke can be exacerbated and caused from too much NaCl consumption.