what are Bards arguements for claiming the share of thorins treasure? how does thorin react to bards arguements?

Bard of Lake-town goes tells Thorin that Lake-Town is in ruins partly because Thorin got Smaug all riled up. He also says that it was him who shot the arrow that killed Smaug. Thorin hence has a little payback to do. Thorin agrees Bard has a point but refuses to negotiate while the Elvenking and his army are at his doorstep.