That seems highly misleading. I think MDMA is far more physically dangerous than cannabis. Many people have directly died from irresponsible use of MDMA, but no one has (directly) died from any use of cannabis. MDMA can certainly be safe and beneficial if taken responsibility, but:

- Doses should generally be spaced at least 2 (many recommend 3) months apart.

- The minimum effective dose should be taken. Even a light overdose can create an uncomfortable, traumatizing, or even physically dangerous situation.

- Hydration and access to cool environments is important. Overhydration can also be a risk, so it's good to have access to electrolyte-laden drinks (Gatorade etc.). Overhydration, dehydration, and brain overheating are the leading causes of MDMA-related death.

- Supplements should be taken to reduce the inherent neurotoxicity even if you do all of the above things right. Some good examples on http://www.rollsafe.org.

It's true that dependence-wise, cannabis is probably worse, though. It's pretty hard to build a dependence on MDMA, as you'll likely only feel the uncomfortable stimulant effects (and other negative symptoms; this can lead to long-term or permanent neuroreceptor damage and dysfunction) if you take it on a weekly or daily basis.