Hi Graham, oofff difficult topic! I have been thinking about this. On the one hand of we all go round in a capitalist system and don't object to it (in a big or meaningful way) then can we really expect people who become rich off of this system to be filantropic good doers.
The real question behind this is: is it ethical to have an economic system which allows to have 95% of the wealth to be in the hands of 5% of the people? And then the interesting thing is that most of us here would say no probably and yet we live in and accept this system.
And then from that question follows if we do accept this system do we then want to tax these people that make it to make up for it? I always think that question is an interesting one since it seems odd to do it expect that.

Anyway I am really curious what you all think, it's a very interesting question