Preventing spread inside a quarantine is a strictly lower priority than preventing spread to the outside, but to claim ignoring that concern is "how quarantines work" is not true at all. Why would you say that?
I guess I don't agree? You can certainly implement additional measures within the quarantine to prevent spread, but the essence of the world is to cut off the outside, not the inside. Any other restrictions are extra. (And, sure, you might be advised to quarantine in your room within a quarantined building—that's two quarantines.)
And in the specific context we're discussing, I agree with the GP that quarantining an office building leaves everyone who's forced to live in that building more likely to get sick than if they all went home for two weeks. However, the purpose isn't to protect the people in the building, but the broader population.
> the essence of the world is to cut off the outside, not the inside
I certainly agree with that. But by my reading, your earlier post is saying that unchecked internal spread is also part of the essence, rather than just saying that worries about internal spread are secondary.
> And in the specific context we're discussing, I agree with the GP that quarantining an office building leaves everyone who's forced to live in that building more likely to get sick than if they all went home for two weeks. However, the purpose isn't to protect the people in the building, but the broader population.
Well nobody suggested sending them home. There are lots of ways to handle it. And they didn't mention any additional safety measures, but that might have been for brevity's sake. In part "Sounds like a good way to get everyone there infected." is also a prompt to elaborate on internal safety measures, if there were any.
Depending on the size of the office, I would argue against method like quarantine in the office
Alternative: let people go & quarantine them at home.
COVID infection is not an one-off event like 10 people get infected at once. They have overlapping incubation & infection periods. Possibly people will get keep getting infected during those 48 hours, and the whole office get quarantined again and again.
edit: on another thought, I don't think my argument holds any weight given how China has been very successful at this.