It was even more confusing to me that the speech bubbles icon isn’t clickable in the topics list.
I opened the topic, and when hovering the icon on the title, the cursor changed to a pointer one.
I assumed that it was part of the topic title (which confused me since I couldn’t click on the topics list, as I said…), but it opened the chat when clicking on it.
I think as well that the chat-linked feature should be way more obvious.