> I can't believe people legitimately think Facebook is spying on them through microphones.

But why? There is a specific feature inside the Facebook app that does exactly this: listens to ambient sound around you to hear the TV ads, radio ads, etc that it can identify to know more about you.

Since Facebook has built a feature into the app that makes it so that the microphone listens to your life, I can easily understand why people think it's spying on you by listening to your microphone. Because it does.