It was difficult for Westerners to understand the heaviness of the invisible power held by those people close to a high-level official, including his secretary and children. In China, the practice 'when a man gets to the top, all his friends get there with him' was practiced since ancient times. The most crucial thing that accompanied this 'under-the-table power' was that blood was thicker than water.
No matter how wise and brilliant a leader was, he couldn't maintain a selfless attitude at all times. When the people around him sought personal gain, the secretary was still okay, but if the people were his children, then no matter how grave a mistake they made, they would still always be his children.
If a subordinate calmly pointed out the mistakes, he might be really grateful at the time, but actually, an invisible cloud would still be left behind, and if this cloud was acted on in the future, endless trouble would be in store.