To my mind, if you think that not immunising is hurting other children, then you will have immunised your child. If you have not immunised your child, then you will have all the various reasons for not doing it that have been stated, and will not blame others for your child contracting it.
Herd immunisation (imo) can never completely wipe out a disease, there will still be different parts of the world that it can be contracted in and brought back, and not all children will take to the immunisations (I've had the hep B vaccine 3 or 4 times now, and I'm still not immune).
I have no idea if any of that made sense... it did in my head.