Ridiculous semantics, when someone says 100% pure they are always referring to actual product being consumed, whether it is a salt or freebase.
Actually it illustrates a serious point: that anyone who says "91% pure MDMA" is talking ****, and that anything else they say is probably wrong. If they got the results from an actual analysis, then it would be quotes as "x% measured as base", because all quant techniques (except NMR IIRC, and that is very seldom used) measure only the active part, and the salt is missed. In that case the person quoting doesn't understand science or the person producing the quoted figure can't do it. If the figure is based on how much the drug was cut, then they are adding spurious accuracy to a fairly in exact mechanic of cutting drugs - which is usually "a spoon of that and two spoons of that". Either way it's just revealing ignorance. Although it still remains far less annoying than all those people who think taking drugs makes them an expert on them. "I took some MDMA once and it was great!" Really, how do you know that's what it was? Get it analysed? Saw an article on the tablet design in a paper? Erowid told you so?
As for legalisation, there are two possible flaws:
1) The assumption that legalised drugs would break the market in illegal ones. As one poster has already said: what, like legal tobacco has killed the market in illegal tobacco? And you can bet Pfizer (or whoever) would be selling MDMA at a price that the underworld could easily undercut. Not to mention mixing huge numbers of fake tablets into the mix via dodgy pharmacists, as already happens with diazepam, among other things.
2) The assumption that everyone who might take these drugs already does. At best this is just a blind assumption by the pros. However, the experience of users of "legal highs" suggests it's not that simple: many people taking them only took legal drugs, and as these were banned they move to new legal ones. Which would suggest that the illegality does act as a deterrent. Yes you say, MDMA is harmless. So, you wouldn't mind large numbers of (say) people driving vehicles off their faces on it?