Very easy answer: they don't.

I'm not a fan of taking zoom calls while my mic picks up the voice of the person that sits across the room. I'd call being able to communicate via voice call without noise issues a need. While it can be done, constantly hearing other ppl in the background during a call just feels unprofessional/sloppy.

Just read the headline?

Exactly.

The best programmers don't actually need to go without interruption all that much nor all that often.

It's really more of a way for the employer to show how much respect they have for their people compared to lesser outfits that don't give a shit.