I think this tells you more about their working and sleeping conditions than it does about how the pandemic will play out on a national scale.

But the article claims it will discuss "How around 50% of us appear to have (some?) Cell Mediated Immunity against COVID-19". If we're seeing farms where every single person falls ill, that suggests that 50% of us aren't immune, though I suppose "(some?)" is a cop out.

So those people in one town did not have enough cell-mediated immunity to clear the viral dose from spending all day in an enclosed space with dozens of coworkers shedding the virus.

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.

Surely it could be true that all population is immune to exposure to exactly half a virion well cooked with sauce, but such an information is pretty useless in any practical way, isn't it?

Half immunity in only certain circumstances is useless for all practical purposes.

No, it is incredibly useful. That means a subset of the population, or a population certain environments, can be exposed and not get infected. AFAIU, every exposure has the chance of the immune system creating antibodies as it does for foreign cells.

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.

I've seen news about bullshit studies from famous institutes in the UK that 60% of the UK's population already was infected by "now" (a month or two ago).

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?

Why would that be an XOR situation?

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.

Boom. That's totally correct. Plus, these articles showing "every single worker" infected or 60% of carrier passengers/prisoners etc. don't do a good job of reporting how may actually sick people there are. Immunity is not all or nothing. It's a relative amount of resistant. Many (likely all) of these "naturally immune" folks (if they exist, and I think the evidence is pretty compelling personally) would get COVID if injected with a sufficient dose of purified virus. Many (likely all) would get COVID if an infected person sneezed into their face. Many (maybe? probably?) would be fine sharing a grocery store with a pre-symptomatic carrier. That's huge if true. Time will tell.