Now I finally understand what these complaints are about, at least I think so. And my understanding is that this bug report is invalid. It’s still quite possible to send private messages to users who have selected “that little setting”. Here’s how:
On the front page, select “New topic” from top top right corner. Next to the “Create a new Topic” text, on the top left of the message box, there is a button with a plus sign. Click it, select “New message”. Write the recipient user name to the “Add user” field, write message, profit!
Now the fact that there is no “Message” button on the user info box could be considered a bug, but as that is not the only way to send messages I’m not sure how serious bug that is.