First off, she was named Mother Teresa, not Sister, and deserves to be a saint. Oprah Winfrey is an entertainment mogul, a celebrity, not a saint.
It is not just millions we are talking about. She is worth over a billion. She is not spending hundreds of thousands, it is millions and millions.
She has to work on television. Everyday she has to have a completely different expensive designer outfit for the show. Then if she attends an event, she has to have a separate expensive designer outfit. This does not include the clothes that she wears at home, to travel, etc. This adds up to a lot of clothes, the majority of which are work related.
The Angel network and the charity activities that we see her doing on the show are involving Harpo. We are unaware of what charities that she contributes to with her own personal fortune.
Maybe we should ask celebrities to publish all their contributions. I am sure we would then see what some of our most beloved stars really give. Until that happens, I don't think any of us should question the motives of someone who has obviously given a lot to a lot of people all over the world.
As far as the people buying the clothes, there are a lot of folks in the world that have $5000. The ones on the Oprah show that bought a dress for $5000 probably think we are insane for spending that much to take a trip to WDW. Different strokes.
I think the vast majority of middle class and upper class people in the US don't understand the kind of money that the super wealthy are dealing with. A family that is doing well, making $70,000 per year, has no clue what it is like to make 200 million a year.