Some people are not aware that their symptoms are linked to the MDMA they take. For example, my BF had sudden vertigo (like the whole world spins in a second), and he has the feel of the heartbeat, like tachycardia, but his heart is perfect. He did not know that those symptoms are linked to MDMA (ab)use. We don't have a brochure to read the "wrong side" of the drug we are taking. I was not aware either, and I also had them. I'm pretty sure that if we ask around other users that consume the substance, we might get a surprise for the amount of people that are actually suffering the consequences without knowing.
Some people don't get negative symptoms, except for maybe being unable to sleep, dry mouth, or anything long term or past the roll. It's that simple. And from all the years I've rolled and having met a lot of different people, it certainly appears that the majority are doing fine. I know for certain at least 20+ are doing well, as if they never rolled all those years ago.
In other words, not once have I seen the majority of users suffering from mdma, especially when talking about it on the long term scale. In reality, I haven't seen or met one person who complained about its supposed long term negative effects.
Most of my friends are just as knowledgeable as I am, if not more, so they are well aware of the positives and negatives of mdma use. I actually learned the basics from them too. I don't think people need a brochure to know; both sides of the coin are well documented everywhere.
There's no way to quantify this, for either side of the argument really. But I'm confident enough to put something on the line for mine. Also, how do you know mdma is the sole cause of your problems? It seems that most people affected so negatively had a lot of negatives in their lives before they even used mdma. It may well have brought out certain problems for you and others, but there are most definitely other factors at play that are tied to your susceptibility. People can have the type of problems described in that thread without ever having taken mdma (yes, I already read most of that thread).
So while mdma might've been part of the problem, it's not the whole story either. This is why myself and so many others are doing well even after extensive use/abuse. Short term problems like lack of sleep and weight loss, well, you have no argument from me there.