Alas! We are out to perpetrate a great sin by killing our kinsmen, solely because of our greed for enjoying the kingdom and the royal comforts.
Arjuna summarizes his stand. He confesses that he and his team are great sinners, as they are fighting with their kinsmen only because of greed for the kingdom and the royal pleasures it bestows! He did not have the larger social dimension of Krishna.
Duryodhana’s crimes started right from young age. Hosting Pandavas in a wax palace and setting fire to it was the worst of them. Making Shakuni play dice in his place and, through deceitful play, sending Pandavas for long forest exile-cum-incognito life was even more cruel.
When Krishna pleaded for mere five small villages for the Pandavas to live, in place of their prosperous kingdom and the royal luxuries it extended, how summarily did Duryodhana deny even a needle point of space for them!
Can such a ruler be allowed to reign? The war was inevitable to redress the grave cruelty and restore righteous rule in the society, not for any personal gain at all. But Arjuna is obviously under delusion!