Jack of Nothing. I understand your wanting to use most of the materiel in a book. It sounds like you are talking about the Advanced Race Guide.
Now to your comment: "its bad enough we have to buy books in order to use anything from them but a chunk of the book we cant use anyways":
I would like Paizo to stay in business. They stay in business by selling adventure paths and other books. So from my perspective, it isn't bad that you have to buy the book of the materiel you want to use. I believe a less expensive alternative is purchasing a PDF of the product.
Now in my opinion there is a very good reason why chunks of materiel are not allowed in PFS.
Take the Words of Power in the Ultimate Magic, for example, this is a distinct subsystem of magic. If it were allowed, it would further complicate things and many GMs would have to learn an entirely new sub system.
Besides, the PFS staff have to decide what fits into the theme of the campaign and what does not.
So in the case of the advanced race guide, they have decided to reward people who volunteer their time at conventions to GM by giving them "race" boons. These boons allow you to play a normally prohibited race.
Just as you would like to play the weird stuff, there are plenty of people who don't want the weird stuff at their table. So the Paizo staff has to walk a tightrope.
Anyways, I hope these thoughts were somewhat helpful.