Downer was just protecting his investment in the Clintons.
Very bad investment going forward from here.
In terms of the donation, that donation was made by AusAid, the agency that back then (until 2007, IIRC) distributed Australia's foreign aid. It was given as a donation to the Clinton Foundation to aid in work related to HIV in the developing world. Critically AusAid was deliberately designed so politicians (like the Foreign Minister) did not decide where aid was distributed to avoid political interference in what were meant to be purely humanitarian programs. Downer did not decide on the donation - the system was deliberately set up so he was at arms length from decisions like that.
But even if he had been, it would have just been a routine aid donation to an American based NGO.