I find it unethical to try to scare people away from recreational drug use, for several reasons. One being the inherent distrust of their ability to form their own opinions, another the kind of linguistic gatekeeping involved where scientific information is withheld through the use of professional or academic vocabulary, and yet another that I don't believe that it works, in my experience it has more often than not the opposite effect and enables or fuels harmful behaviour.
Where do you live, is it actually true that they teach neuroscience in highschool there or did you just make that up? Or do you think one can do a risk assessment from your comments without having a scientific understanding and mental model of the nervous system in general, and the central nervous system in particular?
We know from a lot of informal experimental data that sporadic, responsible MDMA use is, on average, very safe. It's likely to be safer than a long term weed habit, which carries a risk of damaging the heart and things like bronchitis, besides the contamination risks which are relatively hard to test for.
Also, it's not "whatabout-ing". Without a frame of reference the risks you bring up are meaningless to most people and useless in regards to policy. To judge whether you want to take the strictly neurotoxic risks involved in dancing on MDMA you'd need to understand how it compares to other factors in your life. In practice few people go about it in this way, however, and for good reason because the immediate risks involved in going to roll at a rave like party are of a quite different nature. Things like traumatic injury from a fall or sexual abuse or financial harm or the psychological effects of mistaken intimacy with strangers or somesuch.
Having fried a piece out of n thousand axon terminals isn't really a concern to most users, and compared to the drudgery of everyday life it likely feels like a low price to pay for many people. To convince them that this should be their primary concern requires another strategy from you..