Yes, that part about Shulgin was the part I was acknowledging and agreeing with you about. A difference in enantiomeric ratios would make a difference. However, by your OWN QUOTE, an enantiomerically pure batch doesn't have the magic. That makes racemic the better product, AND easier to make. Without going too far into synth talk because it is prohibited, I will say that all of the cost-effective routes to synthesizing MDMA involve going from a NON-CHIRAL (neither R or S) reactant to a chiral final product.
What this means is that, basically, each molecule of starting material and each molecule of reagent can either bump into each other from the top face, or the bottom face. There's a 50/50 chance, and with billions upon billions of molecules in the reaction, statistics start to become pretty much perfect. If you flip a coin an infinite number (or 10^100) times, you're pretty much going to get very close to exactly 50% heads and 50% tails, no matter how many "batches" you do.
There are only 2 ways to get a different result: one is to start with an enantiomerically pure starting material (very, very cost-prohibitive) and dramatically alter the synthesis (the resulting synthesis will not be well-suited to industrial-scale, which adds another layer of cost-prohibitiveness). The other way is to use a very specific catalyst that is able to influence the odds of the bottom vs. top approach at that stereocenter-forming step. Usually, finding the right catalyst for a stereoselective reaction like that takes a lot of research and experimentation, even in the best conditions (university or corporate lab, etc). This would be even less cost-effective than the first way.
Even if pure R or S enantiomers were marginally better than racemic MDMA, it would absolutely NOT be cost-effective to go to all that trouble, and as you've said yourself, they are NOT marginally better than racemic MDMA, they are worse. No one is doing this.
So, once again, while this elaborate explanation is POSSIBLE, there is a much simpler and straightforward explanation that is a hell of a lot more likely, and that's just that people happened to report similar experiences from the same drug.
You are obviously smart and do a lot of investigating into the things you are interested in (drugs, drug chemistry, the biology side of how drugs work, etc), and know a lot more than the average person on the street about them, but you are only scratching the surface of understanding the scope of the science behind what you're reading. This is leading you to a lot of erroneous conclusions that would be obvious to you if you had a strong grasp on the more basic concepts of those sciences.
Before getting into an argument about the synthesis of and differences between enantiomers with a group of people whose education levels on these topics you have no idea about, you should probably have taken organic chemistry 1 and 2, or thoroughly read (cover-to-cover, not cherry-picking) a couple of organic chemistry texts.
It's not a coincidence that people seem to be attacking your posts a lot. : /