This does not in any way suggest that 50% of the general population cannot have enough cell-mediated immunity (or even immunity from a cross-reactive adaptive/antibody response to another coronavirus) to clear e.g. the viral dose from eating at a restaurant.
Half immunity in only certain circumstances is useless for all practical purposes.
Furthermore, if we know that shared living spaces, farm work communes, jails etc are the main source of serious infection, we can hyper-focus on those scenarios and allow the economy to somewhat recover.
We all need to get off our relative high horses, by the way. What is an opportunity to work from home for a lot of us, is a recipe for financial disaster and bankruptcy for many, many others.
They're all tested positive, but 50% of them might have some form of immunity, and are fighting it off like that would a normal cold (or even with zero symptoms). The virus is still in their system, but their bodies are disposing of it without issues.
All these bullshit researchers had to do to prove their point was walk on the street, take 20 random people and test them, surely if such a large percentage of the population was infected, it would be trivial to prove it with tests.
Same here -- if there are obvious exceptions to some bullshit claim that 50% of the people are immune, then just drop that claim already, right?