I would say, if you know this belief and practice, then it would be easy not to become angry. Your choice is to be angry or not. You apparently have chosen the anger. Amongst other things, it sounds like bitterness, also.
Might it be that you are bitter that you did not think to 'cash in' on this "Secret"? Or where is the cause of your anger and bitterness?
At any rate, back in the day that this was NEW AGE, people were not ready. If they were, it would have been there for them. Consequently, it was not and people are 'waking up' and are becoming aware that they can do this.
OH and as for Oprah, she did not do anything but bring this to her show. So, why such condemnation for her? It has been out there, in the movie form, and available BEFORE OPRAH brought it to the network!