If the true value is medium high, any random measurements that lie even further above are easily explained, as that is a low ratio of divergence.
If the true value is medium high, any random measurements that lie below by a lot are harder to explain, since their (relative, i.e.) ratio of divergence is high.
Therefore, the further you go right in the graph, the more a slightly lower guess is a good fit, even if many values then lie above it.
If the true value is medium high, any random measurements that lie even further above are easily explained, as that is a low ratio of divergence. If the true value is medium high, any random measurements that lie below by a lot are harder to explain, since their (relative, i.e.) ratio of divergence is high.
Therefore, the further you go right in the graph, the more a slightly lower guess is a good fit, even if many values then lie above it.