Why would you say that Victor is paying money "out of his pocket" for donating his share of the winning purse, but that Baffert isn't for donating all his 'share' of the BK fee?
I look at that promotional fee as income for Bob, much like a share of a purse is income for a rider. BOTH Bob and Victor are donating income that they could have banked...in other words, out of their pockets.