I am actually quite glad that article is as awful as it is and hope it'll backfire in that it will shine a beacon on this practice.
What cruikshank describes is so commonplace 

and is all to do with the huge power imbalance between aid workers and most of the indigenous population.
I was involved in some NGO work in Uganda some 20 years ago and left utterly disillusioned about how much 'good' humanitarian aid is doing.
I now support MSF because I think there's a place for fast disaster aid, but other than that I think 'International Aid' is rather self-serving.
Btw, when I arrived at the small district town I lived in various local girls offered their services as my house girl within literally minutes of my arrival. And none of them believed me when I said I had no house. White - rich - house. And, to be fair, many local people preferred to work for expats because they were beaten and raped less. And paid more.
I have no idea what the solution is, but clearly advocating that aid workers have a 'right' to sex is just ludicrous.