What people seem to forget is that Oprah is in show business. She benefits financially from supporting these celebrities. And they benefit from her as well. It's a business.
The thought seems to be "Oh, if Oprah gives whoever a thumbs-up then that is THE seal of approval." And then when she gives a thumbs-up to someone we find questionable, we take her to task about it.
It's amazing how much trust people put into celebrities.

jm