I don't believe your first point is proven, nor do I accept that the physical damage done by MDMA during comparable usage to alcohol is greater ... the reverse is true, IMO.
Its not proven beause the government does not allow research on MDMA. However many people I know in RL, and on this forum, report depression, memory problems, brain zaps, seizures, decreased verbal skills, sleep paralysis, intense nightmares ect from ecstasy use. I can assure you, per use MDMA is far more taxing on your body than alcohol.
I think you're equating alcohol and MDMA use inappropriately here. If you compare pills to drinks one for one, you skew things beyond a reasonable point. Let's structure the comparison like this
150mg of MDMA every three months = 3 or 4 drinks on a weekend evening
150mg of MDMA once a month = 3 or 4 drinks everyday
200mg+ of MDMA every two weeks = 6 or 7 drinks daily
Gobbling pills every weekend = full blown alcoholic
So when ecstasy is legal all those people who drink and smoke EVERY DAY are going to pick up ecstasy and use it one every three months? No, just no. Many people have poor self control and additive personalities and will not use once every 3 months, or even on the weekends. They will use it like they use the drugs they are sold next to, every day, and that is not healthy at all.
Obviously, anything (and will) be abused. Also consider that, for many of us, MDMA in not addictive ... nor do we all suffer from a hangover.
Dont suffer from a hangover huh? How many times have you used MDMA? I'm guessing you could count the times on both hands. Everyone, ill repeat that, EVERYONE who has used MDMA alot suffers from the comedown and hangover. Thankfully i'm not to that point yet, but even after only a few uses, spread out over a year I can notice my high is shorter and comedown more pronounced. Maybe if you exercise extreme moderation you can avoid this, but the vast majority of people wont.
It would be awesome if we could make a law that said "If you dont have an addictive personality and can control your drug use then you're clear for MDMA consumption". Unfourtunately I dont think that would fly at all.