I know you have trouble understanding complex financial transactions, but this is a rather simple one.
During the financial crisis, the banks wanted as low of TARP allocation as possible, because the bigger the amount the bigger the problem and banks didn't want to be seen as in trouble (that's why they lied about LIBOR). There were many banks who didn't want any TARP money at all, but were forced to take it. Citi got the biggest infusion because it was the biggest basket case at the time, not because it funneled the most contributions to Obama.