This week's report into abuse of the mentally disabled makes horrible reading. An inquiry found that years of "institutional abuse" had gone unchecked at three treatment centres, four children's units and dozens of supervised houses in Cornwall.
The details of the report will make any sentient being want to turn away and read the sports pages instead: it is too upsetting to imagine society's most vulnerable suffering at the hands of thugs, jobsworths and bullies. But read it we must, if only to better understand the nature of cruelty, and why it should occur at all in the so-called "caring professions".
Examples in the report include patients being forced into cold showers, locked in their rooms, having food withheld, and being drugged to control their behaviour. One man was regularly tied to his wheelchair for 16 hours a day. Another was hit and sexually assaulted; when he asked to move homes, his request was turned down.
There were incidents where staff asserted control over their patients with almost ingenious spite. In one home, they removed all the light switches so only staff could turn the lights on and off. In another, they removed the taps so that residents could not help themselves to water.
The fact that this systematic maltreatment has come to light is obviously a good thing: it means, apart from anything else, that every care home for the learning disabled in England is to be inspected to put a stop to any similar practices.
And yet, the heart sinks. Every scandal like this represents not just a betrayal of defenceless individuals, but another blow to the battered public image of the caring professions. This, in turn, contributes to the biggest obstacle standing in the way of good patient care: bad staff.
Don't misunderstand me - most people who go into these professions are saintly beyond belief. Until recently, I lived with two of them: a married couple, both of whom worked for the NHS as occupational therapists. Tina specialised in helping children with disabilities. Our house was always full of brightly coloured, contraptions - their purpose baffling to anyone not in the know - designed to assist her patients with their posture or concentration.
Her husband, Chris, worked variously with the mentally ill, stroke victims and the elderly. A man of such angelic countenance he was often - to his irritation - mistaken for a born-again Christian, he spent his days devising ingenious ways to help his patients deal with everything from paralysis to paranoid delusions. When ill health or old age eventually strike me down, I pray I fall into the hands of a Chris or Tina. But there's no counting on it. Increasingly, the people who do these jobs fall into two distinct categories: those with a genuine vocation - and extraordinary empathy, patience and ingenuity - for whom improving the lives of their patients is its own reward; or people who can't get a job anywhere else.
The average care home worker earns £6 an hour - £7 if they perform "personal care" duties such as changing incontinence pads. That is about what most supermarkets pay their shelf-stackers.
There are people on the lower rungs of, say, publishing who get paid less. But they stick with it because publishing is an arty, prestigious career, fit for the educated middle classes. What such jobs lack in ready cash, they make up for in kudos.
People who work in the caring professions enjoy neither wealth nor prestige. Although all of us will, at some stage in our lives, require their services, they remain virtually invisible to the world at large: an underpaid, undervalued army, doing perhaps the most important work there is.
When a care worker does make the headlines, it is usually for some act of infamy - further degrading the reputation of the entire profession. Who can blame bright young things for not being drawn to a world apparently populated by bullies and morons?
David Congdon, head of policy at Mencap, told me ruefully: "It doesn't look like an attractive profession, even though it can be amazingly fulfilling. For some workers, it is a choice between working in a care home or stacking shelves. You can tell they're not really interested in the people they're caring for, and that's a tragedy." These are precisely the sorts of workers who, because they don't understand their patients, are likely to become irritated by them - and vent their frustration through bullying or spite.
The astonishing thing is most care workers still belong to the Chris and Tina category. The standard of care for the mentally disabled has improved dramatically in the past three decades. The ethos has shifted from containing patients to helping them fulfil their potential.
Terrible things sometimes happen in care homes, but so do everyday miracles of kindness and creativity. We need to hear more about the miracles to put the horror stories in perspective - and to show future recruits that "caring" can be as good as it sounds.