These two didn't die from MDMA. They died from whatever they took that wasn't MDMA. Why? Because of prohibition.
To blame drugs rather than prohibition is exactly the same as when, during Prohibition, "alcohol" caused blindness, death, and (my own favorite) Jake Leg. These are prohibition problems. Of course during Prohibition, prohibitionists blamed the prohibited drug rather than their policy of prohibition. They still do.
If you're not ready to end drug prohibition, how about testing booths? Testing booths would have saved these two lives. Clubs in Europe have them. But no, not here. You'd get arrested. Why? Because we want our drug users to buy from criminals and die. I mean, seriously, we don't have a system that prevents recreational drug users from dying because prohibitionists, perhaps yourself included, say: "it sends the wrong message!" Because preventable death is such a good message. For shame.
Every weekend, throughout the world, countless hundreds of thousands of people take recreational drugs, have a good time, and live to tell about it. The fact that anybody dies from taking what they think is ecstasy is as absurd (and real) as partial permanent paralysis from a shot of booze.