The Modern Translation
Confucius would look at that thumbs-up and see a small act of pretending. The silent friend knows something, namely that they have no opinion about restaurants, but has not said so. The rest of the chat has the same problem in reverse: you do not know whether anyone is free Saturday, whether the vegetarian can eat at the Thai place, or whether three people have already muted the thread. Applying the line means separating what you know from what you are guessing. You know eight people are coming at seven. You do not know who is in. So stop sending open questions into the void and send a precise one: 'Thai place at 7, reply yes or no by tonight.' It sounds bossy, but it simply admits what you lack, which is answers. Silence turns into a count, and the thumbs-up person finally has to commit.
The Text-Message Version
Try It Today
Before lunch today, pick one open question sitting unanswered in a group chat, like a plan, a date, or a gift split. Rewrite it as a plain statement of what you know plus one yes or no question, and send it. Then notice how many replies arrive within an hour compared with the vague version, and who finally speaks up.