Criticizing doctors is a bit like criticizing teachers or nurses. As Health Secretary Jeremy Hunt has learned to his cost, there are some professions whose reputation borders on the saintly, and the merest hint of criticism can blow back and make you look monstrous.

This isn't a healthy way to view any profession, but it's particularly wrong for doctors. Unlike nurses and teachers, most doctors can expect to earn enormous salaries over their careers, several times what most people can hope to earn during their lives.

The median wage for a consultant is £110,000/year, and for GPs it is just under £100,000/year. This does not include money from the private sector, where many NHS doctors moonlight to earn more money.

Although junior doctors claim to be underpaid, their base starting salary is around £22,000 – 83% of the overall average UK wage – and within a few years that will rise to £30,000. The Department of Health estimates that, once overtime-like pay is factored in, they can earn an average of £40,000 even early on in their training.

All but one issue has been settled – the issue of compensatory pay for Saturday work

There's nothing wrong with high wages, of course. But the doctors' strike is all about money. The old system of banding, which effectively paid junior doctors overtime for working more than forty hours a week, is being done away with in favour of a simpler system, and some doctors (those who work unsociable hours, for instance) will lose out.

It's not unreasonable to be annoyed by that, and everyone should have the right to try to get more money from their employer. But doctors have framed this as being about patient safety and more, when reports from the negotiating table are that, of sixteen issues in contention, all but one have been settled – the issue of compensatory pay for Saturday work.

If the issue is pay, why should the other side of the dispute – taxpayers – be expected to pay more? The main justification for paying doctors more would be charity – they deserve more than they're getting, or it's unfair to cut some doctors' pay.

But the NHS isn't a charity that operates for the benefit of its staff, and it has limited resources. More money for doctors means less money that can be spent on NHS patients, or indeed on other NHS workers.

Some doctors say they'll quit, or leave the country. OK then, if that ends up being a big enough problem, we'll need to offer them more money. But that seems unlikely. Medical school places are heavily oversubscribed and there does not seem to be any shortage of reasonably smart people who would like to be doctors – in 2014, there were 125 applications for every 10 Pre-clinical Medicine places through UCAS.

In fact, the number of doctors, and of people who can perform some of the jobs doctors do, is tightly constrained by the government, backed by the British Medical Association, which in 2008 voted to limit the number of medical students and for a complete ban on opening new medical schools.

The number of doctors is tightly constrained by the government, backed by the British Medical Association

We're not at some natural limit to the number of doctors our population can bear – contrast the UK's 28 doctors per 10,000 people with Spain's 49 or Germany's 38. It seems to me that the BMA has an obvious motive for wanting to keep numbers down: more doctors means lower wages. And good luck to any government that tries to take it on.

The BMA is extraordinarily powerful. It is possibly the UK's strongest union, strong in part because many people do not realize it is a union. Like most unions, its job is to protect the interests of its members, even at a cost to everyone else. But unlike most unions, it is not just self-serving – it is also obsessed with clamping down on personal freedoms like the right to drink and eat unhealthy foods, in the name of "public health".

It's one thing for a union to try to make some money out of you; doctors want to be thanked in the process. Doctors seem to think they have the right to tell other adults what to do. I've debated doctors who've laughed at the idea that adults should be able to drink even if it harms them.

Because doctors seem like nice people who cure us when we're sick, we give them a pass for paternalism that would make Mary Whitehouse wince, and for salary demands that most people can only dream of

For them, the only thing that matters is the physical harm caused by booze, cigarettes and hamburgers. Some can't think of anything in life more important than lifespan, and want to stop anyone else maximizing for anything else as well. For them the pleasures of drinking, smoking, eating, which normal people pay billions of pounds a year to enjoy, are irrelevant in the face of the harm these things do. But a cost-benefit analysis that ignores the benefits is worthless.

Because doctors seem like nice people who cure us when we're sick, we give them a pass for paternalism that would make Mary Whitehouse wince, and for salary demands that most people can only dream of. That's given them a huge amount of influence. The areas where civil liberties are most threatened are all areas where doctors want to make us healthier, unhappier people.

Of course, during their day jobs doctors do plenty of good work. So do pilots, engineers, chefs, accountants, painters and theme park safety technicians.

At the margin, it's not clear that a bright young person would do the most good by becoming a doctor: when we factor in the doctors who are already out there, and the fact that lots of other people are willing to be doctors, even a would-be medic who is more skilled than her colleagues probably saves an extra 20 lives during her career.

If she donated 10% of her income to effective charities throughout her career, she could save about 600 lives. If she did that as an investment banker earning even more than the average doctor, she could save thousands of lives.

I'm sure that most doctors are good people. But some have over-inflated ideas about their role in society. They're not priests here to tell us how to live our lives, and they don't have any more right to a massive salary than anyone else does. We should be less afraid to stand up to them, and to tell them where to stick their pious lectures about how lucky we are to have them.

Sam Bowman is Executive Director of the Adam Smith Institute, a libertarian think tank.