"But that guy, he endured it. The one who should be hating this world the most, endured it!"
Up until the Courtesan of a Nation arc I thought Gintoki's burden was feeling helpless, unable to save Shoyo-sensei from being arrested. And then during the Joui Wars unable to save Shoyo-sensei's life, unable to protect what's most important to him.
But this chapter just adds a whole 'nother tragic level to Gintoki's past.