I used a lot of MDMA 20+ years ago. I was immediately aware, on trying it, that it was neurotoxic. I don't know how I knew that, but I did. However, after I quit I saw no evidence of permanent damage. As a fairly high-level software developer, I'm pretty sensitive to the state of my brain, and I don't recall ever experiencing difficulty working more than 2 or 3 weeks after taking MDMA.

Also, I only heard about this right before I quit, but a lot of the toxicity can be averted by taking 20mg of fluoxetine 3 to 4 hours into the experience. (It diminishes the drug effect, so you don't want to take it too soon.) The theory I heard is that MDMA or, more likely, one of its metabolites, binds to serotonin receptors and damages them. Taking something else that binds to the receptors, then, can help protect them. I tried it once and it seemed to help. St. John's Wort might work too, and is easier to get.

All that said -- I agree that people should be more careful with it. It's a potent psychoactive drug that's harder on the body than most of them, dehydration being a real risk.