WHY WAS VIDURA SURPRISED?

When Vidura was counseling his half brother Dhritarashtra that he should not give in to Duryodhana's intrigues and plots, Duryodhana became enraged..demanding Vidura be thrown out of the palace and whipped left nothing but his breath.
It is amazing to me and I'm trying to picture it.

The account is that Vidura was surprised by Duryodhana's harsh response. Why would Vidura be surprised? He knew well the degraded character of Duryodhana and his violent temper and his inclination to impious activities... the atrocities Duryodhana had already done to the Pandavas and Draupadi personally. Why was he surprised at Duryodhana's vehement response? Was Vidura naive? 

Vidura was not speaking from a political stance. He was speaking from the position of wise counsel based on sastra. A good son can liberate the father but a bad son cannot. His argument was that Duryodhana would not be able to save Dhritarashtra and the family because Duryodhana was inimical to Lord Krishna's devotees. 

But Duryodhana retaliated from a political position. The Pandavas are my enemies they stand in the way of the goal I want to achieve. Duryodhana could only see the Pandavas as enemies blinded as he was by his ambitions. 

Srila Prabhupada compares a bad son to blind eyes.They do nothing but give problems. Better to have them taken from the sockets. Which is what Vidura was advising. But Dhritarashtra was also blinded, first physically but even more significantly spiritually. He was blinded by his affection and attachment for Duryodhana. 

But why was Vidura surprised when Duryodhana retaliated against Vidura's advise that he Duryodhana should be disregarded and abandoned? Wasn't it obvious that he would become angry? Doesn't a snake strike if he is kicked?