As far as I can tell, all the recording, storing and transmitting of audio from the microphone happens after 34 minutes in, after the point where they start hacking the TV and telling it themselves to do these things.
LG's advertising features appear (from what they discover before 34 minutes in and from the clips of the LG execs boasting about their ad platform) to be concerned only with what's played on the TV (and networks, devices, ..., but not microphone audio).
If I'm wrong about this, I would appreciate a timestamp for where in the video they show LG actually storing and transmitting audio recorded from the microphone.