There are no subtleties. The post contains a specific example in Google Meet, which is used by "the general public" and not by anyone "already trained to see this pattern in all other software". It's confusing for a lot of people.

Have you ever watched a "normal" person try to complete a task on a computer? They routinely click the wrong mouse buttons (or double/single click when they should single/double click), close windows, press in the wrong places in the GUI, and generally fumble around until they get the task done. But they don't get exasperated, because they have been conditioned to expect that computers are confusing, and they persist on with their work. And that's why "normal" people think that computers are mysterious complicated beasts.

Because the UX sucks. Everywhere.