It's not an economic or political weighing up of pros and cons, just modelling of the likely scale of case rates in the light of what look to me to be very balanced assumptions about transmission, and updated already to show the impact of the Indian strain being a bit more infectious and/or a bit less affected by vaccines
But they're not bothering to actually model the health risks, 1.2 million inactive adults, being an inactive adult costs more than 10 QALYs, how many QALYs saved by a lockdown - nothing to do with economic or political benefits, I'm only talking about the health benefits, it's the continued myth that lockdown, isolation, closes do not have any harms to health, so you only need to look at the positive side nothing else.
Now it's not as simple as the QALY's above of course, because that inactivity can be reversed, so it's it's not that simple measure, but that does need to be included, and inactivity in the vulnerable is even more relevant as it specifically harms their ability to fight infection in small timescales.
kids "rampaging" in groups is entirely legal unless there's 31 of them surely?