The stuff on heroin is biased towards how the drug is when illegal.
Its not in itself powerfully addictive. It feels nice because it cradles you in a warmth and sublime carefree feeling about the world. All pain, physical and emotional becomes unimportant. If we are honest this is a state that is supremely desirable. So it's no surprise that a journey into this land is repeated or desired.
But I'd venture that more people venture into that world than become trapped in it.
The destructive side of heroin only manifests because of its illegality. If it was available at its true cost and marketed normally to those who wanted it then it might be like coffee is. People who get a regular supply of clean opiate can function absolutely normally as someone who smokes and is addicted to cigarettes.
The demonisation of heroin and opiates only occurred once the hidden modern slavery of humans to the usury system took hold. Industrialists needed labour and people being lost to their system was a loss to their bottom line.
Not true.
If you look at the use of Opium from 1800 to 1850 (totally legal and available all that time) - in 1800, there was already plenty of anecdotal evidence and a general knowledge that opium lead to early preventable death, although many thought it was deliberate death - especially suicide and infanticide (one infamous panacea, Mrs Windslow's American Soothing Syrup, a mixture of sugar syrup and opium, expressly recommended for the teething infants of the poor, had its creator dubbed 'the baby killer' by 1810 - although opium was a standard cure for many childhood diseases at the time, and as opium decreases appetite and takes away pain, it might also have been used to deliberately hasten or palliate the death of a supernumary infant that was going to starve or freeze to death anyway.)
Likewise, apothecaries knew the demand and addictive qualities of opium, and the resulting obsession and madness, and there were advises published at the time to help apothecaries identify mad men who ordered large doses to end their lives, from regular uses that ordered large doses to keep pace with their tolerance for the drug. Even with this confusion of causes and lack of scientific evidence, the sheer number of people dropping was convincing enough for most nineteenth century people to believe that opium was in itself a cause of deaths ( there was some scientific study, eg. Friedrich Accum, Thomas Wakeley, but medicine was not as strongly evidence based as it is now, nor chemistry as exact a science, and there was also confusion as to what was 'poisoning' and what was 'medicinal', and as much or rather more concern about the possible evils of adulterants in the opium, as its inherent harmful properties and potency, so the data is flawed.)
It is true that there were many people who took opiates as patent medicines without becoming addicted but there were many more people who were addicted to opiates in the ninteenth century. (As it is true that in this modern day, there are many cancer survivors and burns victims who have used morphine regularly for pain relief, acquired a tolerance as a consequence, experienced withdrawal as a consequence, and yet did not go on to use opiates after - although there are also heroin addicts that first acquired their habit as a burns patient or similar.)
The industrial revolution was not what started the demonisation of heroin. The expansion of opium cultivation for the use of a passive bonded working class that would spend eighty hours a week on the factory floor regardless of health or saftey, was an important factor in the rampant expansion of capatalism and its absolute power over the working class before unions were legal or Marx was published. Then, the opium of the people was opium. The first organized efforts to oppose the opium trade were by Quaker groups who were partly motivated by the effects on the health of opium users (not distinguishing medicinal from recreational- that was a feature of the next century.) but mostly campaigned for the abolition of the British government monopoly on the cultivation of opium in India, and to stop the unfair pressure on the Chinese government to force it to trade in Indian opium. So while health was an issue, the main argument was moral - the opium trade was leading to corruption in British government, and overt and covert wars, arms escalation and slavery in India and China. Even that really did not get off the ground until the 1870's, and it was not until the 1900's, when the anti-opium cause became more closely aligned with the anti-asian cause, that the first restrictions came in, along with the White Australia policy and various legislation to prevent Chinese and Indians making money off of white people.
As to its lack of addictive qualities, and lack of harm to health in a pure and legal doses, the evidence shows otherwise.
In the seventies, I can remember people talking, not always facetiously about taking 'a bex and a lie down', and old ladies, in their sixties, being in the habit of 'having a powder' with their tea. Until the 1930's, Vincents and Bex powders had been a mixture of morphine and aspirin. After, just aspirin, but opiate habits die hard. There is lots of good scientific evidence available now, that while not everybody who 'ventures into that world' becomes 'trapped in it', there is a much higher likelihood of a person who tries heroin becoming addicted to heroin, than there is of a person who tries alcohol becoming addicted to drinking, or a person who tries nicotine becoming addicted to smoking, or even of a person who tries crack becoming addicted to meth. It is an extremely addictive drug and one that can build a tolerance very rapidly. Even people who are not genetically biased to addiction are more likely to become addicted on exposure to heroin than nicotine (Although if one of your parents was a heavy drinker or an addict, it is very likely you carry genes that predispose you to becoming addicted to drugs, and are 40-60% more susceptible than a person who does not have genetic predisposition.)
As to "People who get a regular supply of clean opiate can function absolutely normally" - look at Micheal Jackson. What do you think killed him? Jackson had been taking a pure, legal, synthetic opiate (Demarol) with medics assisting and auditing his use, since he suffered burns during a Pepsi commercial in 1984. True, spending half your life underweight, depressed, constipated and living in la-la land is not as bad as having amputations due to injecting non-injectable drugs, or spending sixteen hours a day on dialysis due to Hep C, or being found in a sleazy hotel in Thailand three days after you die an excruciating death alone from injected rat-sac courtesy of your trusted drug contacts, but even with a pure supply and medical assistance, Micheal Jackson lived 30 years less than the average American man, and had worse cardiopulmonary health, and just suddenly stopped breathing, the way you do when you are under the influence of drugs that suppress the CNS -the way opiates do.
If you think pure legal opium is not a killer drug, you are kidding yourself.
That said, I do think all drugs should be legal and regulated, and addictive drugs that are known to be harmful to public health should be restricted. It seems insane to me that we sell cigarettes at petrol stations - flammable liquids and smouldering butts, not a good mix. Or that it is legal to smoke cigarettes on high fire danger days. Or that it is acceptable to put our police forces and emergency wards under so much pressure on Friday nights just so nightclub owners can make a bigger profit. We should have a floor price on alcohol and ban service of the stuff between midnight and noon.
And your argument that drugs do not free the mind, is too eloquently evident to contradict.