America, Haiti, and the IDB

A disturbing article in today's Guardian, here, about how the Inter-American Development Bank, an organization chartered to help countries social and economic infrastructure needs be fulfilled, is being used as a political tool to bully Haiti into having the government America wants:
Internal emails reveal that a US legal counsellor inside the IDB proposed to the US Treasury that, though the loans faced no legitimate technical obstacles, the US could effectively block them by "slowing" the process. Indeed, by requesting further review of the loans, Haiti would have to make scheduled payments before the funds were even disbursed. "While this is not a 'bullet-proof' way to stop IDB disbursements," the counsellor wrote, "it certainly will put a few more large rocks in the road."
The reason?
In 2001, US officials threatened to use their influence to stop previously-approved IDB funding unless Haiti's majority political party submitted to political demands to accept a particular apportionment of seats in a Haitian electoral oversight body. Soon after, at the behest of the US, instead of disbursing the loans as planned, the IDB and its members took the unprecedented step of implicitly adding conditions to require political action by Haiti before the funds would be released. These actions violated the IDB's own charter, which strictly prohibits the bank and its members from interfering in the internal political affairs of member states.
Why can't we just keep the promises we make? If we don't want to keep them, why do we make them in the first place?