The foundation itself isn't completely blameless. They have some of their n billions invested* in the very companies who's environmental and social policies are are causing harm to people they are trying to help with their clinics, etc.
*I heard about this several years ago so would be happy to be told they've changed this. Their response was that the fund management and philanthropic arms of the foundation were firewalled and the former's directive was to simply maximize growth. I find this unfortunate at best.
It appears that the Gates Foundation works under certain contstraints, dictated of course by the elite family which runs it. For example, they appear to strongly respect intellectual property and corporate profits, as you might expect from a Microsoft founder. (This may take the form of ensuring that companies like Monsanto benefit from aid.)
There was an informed article in The Nation which touched upon the undemocratic vision the Gates Foundation allegedly has; people affected by poverty do struggle to fix their own problems in a self-governing way. Elite benefactors like Gates or Soros may conceivably help to strengthen the systems which make it hard to self-govern, along with whatever benefits they accomplish.
(Incidentally, I don't see why Gates is considered a particularly predatory businessman. He just happened to be the one who succeeded, as usually happens; and other businesspeople don't like an entity with the resulting market power. He might be a much nicer guy than many of his competitors, for all I know.)