In value-at-risk terms, Starbucks' hedging requires a negative amount of capital: they need more cash on hand if they refuse to hedge. With a given capital structure and no coffee hedging, there's a possible coffee price X that would wipe them out. With hedging, they can place an offestting bet that coffee will rise; then they're indifferent to that price fluctuation. That's one less way for them to unexpectedly lose money, so their results in the aggregate would be less aggregate.

Plus, the buckets of money thing is a canard; Goldman has to earn a percentage on their capital, just like anyone else. If they have 10X as much equity as Starbucks, they need to earn 10X as much net profit to get the same return. And ceteris paribus, that means taking 10X as much risk.