It is a consolidated spot for hanging out, talking off topic, talking about whatever, and sometimes even talking about LGBTQ issues.
There is a main Lounge thread for GD here GD Lounge # Reforged Shadowlands (Part 2)
And there is one on the CS forum too.
If you find the thread to be an issue, at the bottom you can use the drop down menu to mute the thread and it removes it from your viewing list.