I disagree with that blanket statement pertaining to Lounge threads.

Yes, there is off-topic content posted to Lounge threads, as that is one of the purposes of them.

However, the reason why the Lounge thread in the Delta SkyMiles forum is called The Delta Forum Lounge Thread — Everybody is Welcome! is to allow those who are not sure as to where to post a question or seek information on-topic to the forum to do so without fear of being vilified — especially new FlyerTalk members...

...and here is but one of a number of examples of that purpose. Please keep reading once you click on that link, as another example immediately follows the one I have chosen...