It was hard not to sympathise with Nicola Sturgeon at First Minister's Questions on Thursday. Having accepted the advice of her clinical advisers, and decided not to close schools, universities and large gatherings, she risked being accused of allowing people to die needlessly.

Minutes before she rose in the Scottish Parliament, the Irish Taoiseach, Leo Varadkar, declared a blanket ban on all meetings of more than 100 people. A measure like that would not just mean schools closing, but the Scottish parliament going into lockdown.

Ms Sturgeon was painfully aware that many of her ardent followers believed Ireland is taking the right policy, and that the First Minister was allowing herself to be dictated to by Boris Johnson, a PM they loathe.

READ MORE: Coronavirus in Scotland: All Scottish schools could close from end of Easter break 

The First Minister's discomfort was obvious as she, on the one hand, advised people to stay at home to stop the symptoms spreading, while arguing that school children should continue to be exposed by attending school. It seemed to defy common sense.

If only Scotland could make its own decisions, they moaned on Twitter. But the First Minister had made her own decision. She agreed with her National Clinical Adviser, Jason Leitch, as well as the UK Chief Medical Officer. It was her call.

Politicians, not scientists, made the decision not to close schools. And she was right to do so. Even though she appeared to contradict herself by arguing for the cancellation of events involving more than 500 people.

She justified this in practical terms as being necessary to release police and ambulance staff for coronavirus work. The UK government followed suit later, for the same reasons. This was not a change in infection-control policy. But the wisdom of crowds was taking over.

Sports like football are already self-isolating. Book festivals, conference and concerts are spontaneously shutting up shop. By tomorrow, parents may be ignoring government advice and keeping their children at home.

Another problem for the First Minister, as she tries to keep in step with the other nations and regions of the UK, is that Britain looks out of step with the rest of the world. Not just Ireland but countries like Belgium and Norway have resorted to lockdown.

Politicians like Rory Stewart, the former Tory Development Secretary, took to the airwaves to argue that the government had got it all wrong. We should be shutting down immediately, cancelling sporting events, banning large meetings, keeping people in social isolation.

After all, that's what China has done. Coronavirus has peaked there. So why aren't we doing the same?

Whom to believe? Paranoia is the default condition of social media and all weeks people on Twitter have been claiming – in all seriousness - that Boris Johnson is content to see millions of old people and poor people sacrificed on the altar of the economy in order to justify Brexit.

Then there are those who believe that Dom Cummings, the Prime Minister's saturnine adviser, is a eugenicist conducting an evil experiment under the guise of “herd immunity”. The Brexit culture war has morphed into a coronavirus culture war.

Herd immunity is the doctrine that the epidemic is allowed to spread through the community so that the population acquires antibodies. Eventually, enough people develop immunity through exposure that the disease cannot spread – much as children do when they are exposed to diseases in school.

READ MORE: Coronavirus: Scientists claim UK strategy is 'risking lives' 

However, this well-respected epidemiological approach implies that some people just might die in the short term in order to save a lot more people dying down the road. It means allowing the virus to run through the community, rather than locking down and minimising the immediate risk of infection.

Herd immunity is central to the Government's coronavirus strategy. According to the epidemiologist, Professor Graham Medley, on Thursday's Newsnight, the only way we can acquire it, given that there is no vaccine yet, is to allow “everyone to be infected”. He'd like all older, vulnerable people to be sent to Scotland, so that there could be “a nice big epidemic in Kent”.

He's not serious of course. Like Boris Johnson's remark about “taking it on the chin”, the Warwick University epidemiologist was trying to explain disease modelling to a lay audience. But you can't use metaphors in the age of Twitter.

Herd immunity has been attacked as social Darwinism – survival of the fittest. Social media has become a factor now in epidemics. Herd immunity attracts the kind of venom and abuse that is normally associated with the transgender debate. The free-floating animus that resides on that platform instantly descends on anyone trying to explain what the scientists mean.

“How can you sit there and let people die!” they screamed.

The simple answer is because it's what the Chief Medical Officer and the National Clinical Adviser say we should do. They argue that if we go into lockdown, and inhibit herd immunity, we risk another wave of the pandemic when the lockdown is lifted or breaks down.

We live in a democratic society, and the kind of draconian restrictions imposed in communist China would not work here, or would not work for long. We can't turn the country into a prison.

Moreover, complete isolation would mean millions losing their jobs, the economy collapsing, social services in disarray. In epidemics, people don't just die from the disease. They can die just as easily from losing their livelihoods.

The last thing the NHS needs is thousands of health workers staying at home to look after children locked out of school. The health service doesn't have the capacity right now for a major epidemic – hence all the talk about "flattening the curve". Within a couple of months it may be in much better shape to cope.

Anyway, as the First Minister explained, closing schools doesn't necessarily halt transmission. Children will still associate with others when they are off school – often in less clean environments than a well-scrubbed classroom. They will often be looked after by older people – the ones most at risk from the collateral effects of coronavirus.

We are a risk-averse society which believes in a risk-free world that doesn't exist and never could. Over the last 30 years, a generation has been brought up to believe that it has a right to be protected from every risk – even the risk of being exposed to difficult ideas. Hence the obsession in universities with creating "safe spaces".

This “snowflake” generation dominates social media and is outraged at the thought that there is something from which they cannot be protected. They believe it must be a government plot, a Brexit ploy; capitalists making a buck out of hardship.

So we end up with people on the one hand condemning Donald Trump for taking drastic measures without understanding the science, and on the other, calling on the government to ignore the advice of its medical experts.

But Boris Johnson is right. The First Minister is right. They are over a barrel. You can't insist that politicians listen to the best medical advice, and then insist that they reject it because it sounds wrong.

The harsh reality is that some people are going to die whatever happens. Politicians can't do miracles; they can only do their best.