I'm practically certain that there was no ill-intent by LG when conceiving this feature. It was most likely just a convenience thing.
But I am also practically certain, that, eventually, any pile of data will attract ideas you do not want attracted.
Yes, unfortunately the investigative video is implying (or explicitly stating) malice on every detail they discovered, which is harming the overall message IMO.
They hacked the TV OS, then used the TV UI to do a web search with voice-input and observed (still on the UI!) that the voice input didn't stop immediately on silence but kept extending the search prompt with everything said [0].
The OS-hack was irrelevant for this, the whole sensationalism that a listening process is running (and therefore the device is listening to everything) is just drama added to the sober fact that someone started voice-input, the input field is still displayed on the bottom of the UI and keeps getting populated with new input.
There is an important message in this about security hardening, privacy, data protection, but this conspiracy theory that everything is made to spy on you is not helping...
There are multiple recordings of LG executives saying "we own the glass (the TV)", referring to the "LG household", and how they can serve targeted ads by recognizing every device on the network. Just watch the video...
The head of LG ads was banned from serving in a public company for 10 years by the SEC for fraud...