In the crisis at Oxfam, I fear some general points are being under-appreciated.

One is that motives are sometimes over-rated. It is the case that some of Oxfam's critics are animated by a hostility to its campaign against inequality and by an antipathy to foreign aid. And it's also true that, as Simon says, they are more censorious of Oxfam's failings than of the underfunding of the NHS which is perhaps even more damaging.

But facts are facts, whoever utters them. We cannot avoid nasty truths simply because we don't like who says them.

Sometimes bad people do good things, such as alert us to the facts.

And of course, the converse is also true. As Oxfam has shown, good people can do bad things. There are at least two mechanisms at work here.

One is ego-depletion. Working in the most Godforsaken parts of the world is hugely stressful and requires great self-control to carry on the job. Self-control, however, is limited: if we use it all up in one place, we lack it elsewhere. "Work hard, play hard" and the need to "let off steam" are clichés because they are true. Some of Oxfam's workers are extreme manifestations of this.

Another is moral self-licensing. If you can convince yourself you're a good person - perhaps even by being a good person - you give yourself a licence (pdf) to behave badly.

On top of these, there might be a selection effect. Aid work doesn't just attract those with a desire to do good, but those who get off on blood, gore and drama.

There's something else, though. Organizations (or parts thereof) can and do drift away from their original purposes, because the interests or passions of incumbents can over-ride them. This was the gist of Martin Luther's opposition to the Catholic church. It was expressed in Dostoyevsky's Brothers Karamazov, where Jesus Christ returns to the world to be greeted by the Grand Inquisitor: "Why shouldst Thou now return, to impede us in our work?" Niskanen's model of bureaucracy, the iron law of oligarchy and Alex's description of how Capita was in effect run by its salesforce are all different manifestations of this.

All this has a troubling implication. It suggests there might be nothing unique about Oxfam, but perhaps that there are general mechanisms at work here rather than a few bad eggs. And it suggests that organizations need very strong measures in place to check these mechanisms.