When you flag to close as off topic, your flag sends it to the "Close Vote" Review Queue. Higher rep users review the queue to determine if it should be closed or not. They can also skip the queue and just vote to close on the question itself (which will also send the question into the Close Vote Review Queue). Only the higher rep users' close votes show up in the close message.
You can read more about close and reopen vote privileges in the help centerclose and reopen vote privileges in the help center.
