"Appalling" comes to mind. You quote 3 statements of his comprising 5 sentences or fragments thereof. Each sentence makes a different point. Each point is demonstrably wrong, at least in this world. Briefly:
1 - "since government is so inefficient and wasteful, more poor people would be helped if charity was coordinated by the private sector."
Consider Medicare and what percentage of its budget is overhead, vs the percentages of each dollar most private charities keep.
2 - "Americans are extremely charitable, even after the heavy tax burden we have."
In times of economic trouble, like depressions or recessions, when lots of people are out of work or "underemployed" [ie: $7.00/hr doing dishes and janitorial work in a diner 4 hours a day, 7 days a week] the amount of charitable giving drops and drops noticeably. Churches get smaller amounts in collections, food pantries start running out of food, Christmas Wish gets 1 present for every 2 or 3 kids... When people need help the most is often when others are hurting, too.
3 - "The government simply uses its power to decide that ever-increasing amounts of personal wealth be diverted through them — with a cut off the top — to support causes which the private sector could do more efficiently."
Like building the Interstate Highway System, the Hoover Dam, the air-traffic controller network, shaky as that is sometimes, or how about integration, the vote for all women, the FDA, shaky as that is. How about building codes and consumer protection agencies? Private industry actively opposes many of these public goods, like, for instance, the EPA, which tells industry things like " you really shouldn't put too much more arsenic in our drinking water, please".
4 - "I would wager that my job has helped save our economy from the economic ravages of out-of-control environmental extremism."
Up until here, he was just spouting looney right economic bs. When I first read this sentence, I had to re-read your description of him at the beginning because I thought he was claiming to be a politician from his statement. In the final sentence, he does claim to be a politician. albeit not much of one, apparently:
5 - "I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government."
I read this last, then went back to the top and re-reread the beginning of this question. What the hell is he talking about? This is a scientist? His 4th and 5th statements not only totally undercut his current standing as an actual scientist, they also show his economics will be bad, because he will bring his politics to the soft science - shaky as it is! - of economics, and find things like "Roosevelt caused [most of] the Great Depression", and "things would have been wonderful if we had let Goldman-Sacks crash like Lehman Bros. The market would have taken care of the problem, completely and thoroughly, in a matter of months, and then everything would have been beautiful..."
I would truly wish, for the sake of his integrity, both scientific and personal, that these are not representative comments, that they are both the most and only egregious comments in an otherwise excellent book, paper, blog, whatever. Dana, I have always found it difficult to answer your questions, because I spend days reading through references and references of references, and the question is closed by the time I get around to writing it up and trying to post it. But here, I find Spencer to have gone a bit over the edge in his 4th statement: "I would wager that my job has helped save our economy from the economic ravages of out-of-control environmental extremism." If this is his attitude toward his job as a scientist and his job as author of that economics book, then he has lost any pretense of objectivity. A serious, dedicated, and constant striving for objectivity is a hallmark of a good scientist. He's busted on that. He also shows quite a high opinion of himself here, one totally unjustified by the actual science, as far as I can see.
A scientist-legislator, saving money for the public, always in their best interests, of course. Or is that a legislating scientist, a crusader for Truth, Justice, and The American Way. That's fine, if you separate the 2 jobs and wall them totally off from each other. Spencer's last statement: "I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government." tells us flat out he views them as one and the same job. I see a major loss of objectivity and the subservience of science to politics in his statements. It bothers me to say this, but I was not the one to say it first. Spencer was.