Anger is a largely wasted emotion

so I am trying not to feel annoyed but I am also finding that rather difficult.
On Saturday I had the newsletter for a group I belong to delivered by email. It saves paper and postage and that's fine with me. It was the content that annoyed me. 
The group runs workshops. That should be a good thing. The workshops were advertised. Fine. I have no problems with that. 
What is being taught however is a problem. 
I know who will be teaching the class. I know why that approach is  being taken. I also know how they will justify what they are doing. The reality however is that they are allowing their personal prejudice and dislike of me to take precedence over the good of the group. That's not good. 
This person knows that, if invited to help, I would happily have shown people a much simpler and more flexible means of doing something. I have written something that everyone could have used without worrying about copyright restrictions because I would have granted permission to use it. 
But, it isn't that which worries me. What worries me is that someone has so little loyalty to the group to which they belong that they will deliberately deny them information which is of benefit to them.  It means that people will go ahead and do a lot of work and then find that there is another way which is judged to be more acceptable. They won't receive the credit they could for their work.
That's not telling me how much I am disliked. I know the rest of the group won't see it that way and I'll be given a lot of support. This person is simply showing a disregard for other people and the good of the group. That's not good and it bothers me.
That's not good.