I can see how this one might be confusing-
https://grumpy.website/post/0Vp0pSilqbut the site is misrepresenting the state. That user's state is still "muted," the red line indicates that it is a client side mute (so the user who checked the mute box can't hear them, but everyone else can) while the mute icon without a red line indicates that the other user has muted themselves; they're not transmitting audio.
There is a third state- Server Mutes turn the entire mute icon red and is a "far-end" mute. No one in the voice channel can hear that user and the user probably can't unmute themselves.
Looking more at the site I feel like the point it's trying to convey would be much stronger if it went for a quality over quantity approach and/or proposed solutions to some of these problems. A lot of them seem to almost intentionally miss the point of the UI.
For example, the airpods post[0] notes, "Want to listen to the podcast on your iPhone while playing a game on your iPad? Well tough luck using your AirPods for that," which is just completely false.
Sticking to posts like this[1][2] would lead to a much higher quality website imo.
[0]: https://grumpy.website/post/0VaJdRL-y
[1]: https://grumpy.website/post/0VlYhfUMg
[2]: https://grumpy.website/post/0VfEvLg0j