Agree with the first part, but not the second. The drug has to be viewed in its context (which you pinned down very well) when discussing the OPs question and questions about its safety. Alcohol is arguably good for you if you limit consumption to a couple of glasses of wine every other night. Unadulterated heroin would be pretty safe for most people of you set yourself a few rules and stuck by them. This is not how people tend to use these drugs, however.
Incorrect/ reckless use is arguably what makes any drug dangerous. MDMA is very easy to use incorrectly due to its nature (affecting serotonin the way it does, making it a bad choice any sort of regular consumption) and the reasons you listed above. I don't think it's that safe as its neurotoxicity is amplified when used incorrectly and so many people do use it incorrectly. It is VERY safe in certain ways (you probably won't OD for e.g.) and quite dangerous in others (it can change everything about you right down to the core). The fact that people are waking up different, with all sorts of emotional problems, (some from high doses, some from regular intake, some from occasional low doses even) surely reveals that it isn't THAT predictable either.
You acknowledge the first point, but then still seem to, with absolute certainty, pin these 'emotional problems' down to MDMA. You admitted yourself that the market is unpredictable and users do not know what they're actually taking. How can you, with absolute certainty, attribute these emotional problems down to MDMA in the light of such an unpredictable, corrupted market of drugs; literred with myths (tan colour MD is the best! Yeah it should smell like licorice etc etc), profit-drive criminals & 0 regulation. In my opinion, this is what makes MDMA or mandy, molly, pills, sass, gurners, E, ecstasy, rolls or whatever bullshit variant sold, ultimately unpredictable.
Secondly, MDMA is not an impulsive drug and is only difficult to use correctly because of the lack of education & unpredictable nature of the market. Everytime i've consumed tested MDMA I feel no impulse to take it regularly, or even redose, despite how much I adore the experience. Further, for many 'less-educated' people I know, it did not take them long to realise that you can't smash MDMA all the time and have the same experience. For this reason, many of them limit their MDMA consumption just because it doesn't work or, as some here like to call it, loses the 'magic.'
Just because some people come on here reporting emotional problems from high doses, regular intake or even low doses, holds no testiment to the true dangers of MDMA. As we both acknowledge, these users do not, typically, test their product nor have any idea of how to safely consume the drug. Thus, we have no idea what they've actually been taking regularly, nor how much. For this, I blame the black market & the piss-poor education provided. Just 5 seconds reading Talk to Frank makes me sick to my fucking stomach.
Also, it is important to mention that this forum tends to provide an overview that is generally biased. Most people end up here due to experiencing problems with 'Ecstasy' to which they then become educated and learn about the drug. We see many threads saying 'I took this now I feel bad - will it last forever' but not many saying 'I've been taking this regularly and I feel fine' although I've heard a few stories of the latter, the former outweighs this forums overview. Is this because the former is a more accurate representation of the dangers, or because those who experience no problems don't bother seeking help on the internet - who knows.
Just a point regarding neurotoxicity, it is thrown around like something people actually understand, but they don't and nor do I. The reality is, oxidative stress is a very, very common occurence for human cells. For example, exercise causes oxidative stress, the decline is cognition that occurs with age is, in part, attributed toward oxidative stress. All this discussion about neurotoxicity, oxidative stress etc is not relevant until very large doses - or at least thats what the literature suggests. 5mg/kg is a 'neurotoxic' dose but is well above the range for a usual recreational dose, not to say people don't take that much. Smaller doses are not typically defined as 'neurotoxic' because we are able to naturally buffer oxidative free radicals thus resulting in minute damage, if any at all.
Overall, i'm not trying to dismiss the potential dangers of MDMA. Quite simply suggesting that we cannot, with 100% certainty, attribute everything seen or heard about, whether in this forum or elsewhere, to MDMA for the aforementioned reasons. In my opinion, the drug itself is not unpredictable rather the climate from which its sold in. After all, if the science behind MDMA, formulated through the review of literature that actually controls the substance, pointed toward the drug as being unpredictable, I'd highly doubt any research would gain ethical consent and funding for the treatment of PTSD, especially in a society that is so driven against drugs.