can't websites already do this?
There are some sites I use that, when I get distracted and do something in another browser, pop up a notice to the effect of "are you still there? click [here] to keep the page open" (some have a "you will be booted in 20 seconds" countdown). So, unless the real reason is employee "time on task" tracking (as mentioned above), I don't know that this is doing what can not already be done.
I would expect Chromium-based browsers whose developers claim top concern for users' privacy will have "turn this nonsense OFF" toggles easy to find and adjust, if this hell can not be disabled "at the source" by the browser coders.
Also, I "attend" many tele-meetings wherein I don't really DO anything besides listen, watch the presentations, and maybe toss a question into the chat window at the end. Will my lack of participation be considered "away"?
I agree that this would seem to cause more problems than it notionally purports to solve.