I remember going on a sponsored walk for Oxfam - it must have been a good forty years ago - and I have donated modestly in the years since.
You feel safe giving to Oxfam: its proper name is or was the Oxford Campaign for Famine Relief and you know exactly what it does.
No you don't.
There was a recent case with an actress Scarlett Johanssen who as well as being an Ambassador for Oxfam was in an advert for Sodastream, which is made in ISRAEL. Oxfam had decided to enter the Arab / Israeli dispute on the side of the Palestinian Arabs (I don't know whether Hamas or Fatah) and in the ensuing row Ms Johanssen, to her credit, severed all ties with Oxfam.
Note that Oxfam's involvement in the West Bank was nothing to do with famine relief. It was purely political, the managers taking the money donated by honest folk for the relief of hunger and applying it towards their own political aims. It doesn't matter which side you take yourself, this diversion of funds should outrage you.
Now we read that Oxfam has decided to give its views on the gap between rich and poor - not in Africa, where it is extreme and identifiable as a cause of hunger, but in Britain. It has announced, pompously, that the five richest families in Britain have wealth equivalent to that of the poorest 20%. This is not a complaint that the poorest 20% are suffering from famine (they're not) just that they have perceived a sin (rich people tend to be rich and poor people tend to be poor). They have got involved, as in their Middle East caper, with politics, pure and simple, and using your money to do it.
Personally I shall never donate to Oxfam again.