In plain words
So they look on as though their knowledge, their position and their skill of intellect had simply been wiped out. Though such people do not practise Adharma, they appear as men who encourage Adharma. Here is a small example of this.
In the Mahābhārata, Dharmaja recognised that this war would bring great danger to the world itself, and sent Kṛṣṇa as his envoy. Kṛṣṇa entered the full assembly and went on describing well the dangers that would come of it, and these circumstances. But even such eminent scholars as Bhīṣma, the great jñānī, Droṇa, Kṛpācārya and Aśvatthāma were listening well to these matters. But though they heard, it was of no use at all. Only because they had joined the side of the Kauravas, who were wicked and evil, only through their company, they too turned into men who encouraged it. Vidura, who recognised this Adharma and this wrongdoing, tried to stand up to it. He reasoned with them in many ways: this was not good; we must put into practice the holy sayings of Kṛṣṇa Paramātma and make fitting amends for this. But it was of no avail. Thinking it better to go on some pilgrimage than to stay beside these wicked, evil men, Vidura renounced that very kingdom and went away. Bhīṣma, Droṇācārya and Kṛpācārya, all of them, because they had eaten the Kauravas' salt and tamarind, wanted to be of some kind of help to them, and from the attachment and possessiveness of ‘We have lived in their kingdom,’ went on living in the very kingdom of these wicked men. Every one of them was a great ācārya. Every one of them knew the matter of Dharma and Adharma. They were men who had examined what is eternal and what is transient. All this knowledge, not being in practice, turned out to be useless. So, in the end, just as the Kauravas died in the war, these ācāryas too died in the same way. Those who have the power and ability to defy injustice and wrongdoing and set it right, and yet do not try to set it right, are equal to the wicked: so Kṛṣṇa held. Even while such injustices, wrongdoings and misdeeds take place before our very eyes and we merely watch, the people who cannot stand up to it at all and cannot correct it also turn into men allied with that wickedness. That is why these men too have to suffer the consequences of the wicked.