Ok, I responded without reading the article, so perhaps my wording was a bit off since I thought they were talking about the Secret Service costs.
After reading the article, my opinion remains the same. Most of this is pension costs and I have no issue paying a pension to former presidents. I think there could be some issue with some of the costs for offices, supplies and equipment, but if those are dictated by requirements to exchange classified information then I would classify them as necessary.