Because USAID supports pushing artificial contraception. See here about Georgia. See here about Romania (just two examples).
Because USAID supports and provides cover for organizations that push abortion (and if that pesky law against US foreign aid being used to perform abortions, you can trust that they’d do that, as well). See the official USAID website for more.
Because, as a matter of official Obama Administration policy, USAID pushes countries into liberalizing laws to allow rampant homosexual conduct. See this from The Telegraph. (If you don’t remember them threatening Uganda all on your own).
For those three reasons alone, no Catholic should support USAID. Not until they change their tune so as not to promote immorality.
Don’t get me wrong: I think that providing assistance to help build infrastructure, improve education, and help other countries learn to stand on their own (so that those other countries’ populations don’t feel a need to migrate because of economic pressures) is a really good thing and is perfectly consistent with the principles of solidarity and subsidiarity. But the US Government, particularly with the morally corrupt Obama Administration (not that prior administrations were perfect…not hardly…), has proven that its agenda has little or nothing to do with helping other countries build up, its agenda is to support corrupt friendly governments and to help spread American cultural decadence.