Read: Economics as Religion
the 15th edition, then by Samuelson and Nordhaus, was the textbook assigned to the introductory economics course I took in the nineties. Hence, it often seems that Nelson does not write about the field of economics but only but this, admittingly influential, textbook. Other protagonists, the antipole, are the various members of the Chicago School, most prominently Frank Knight.
The observation that many early economic analyses were based in (unexamined) presuppositions that were more like articles of faith is not enough to convince this reader of economics as religion. The observation that some economist assiduously follow their agenda, may it be driven by intellectual curiosity or political conviction, is not enough to convince this reader that economists are secular priests.
Nevertheless, the links between Catholicism and leftist Progressivism on the on side and Protestantism and more right-wing Libertarianism on the other side and their respective protagonists in economics are interesting. Religion influences, of course, culture, and therefore, it will also influence (economic) thought. Still, the increasing secularization, agnosticism, atheism, non-religiousness, and the move towards scientism does not make economics a religion.
In spite of Nelson's failure to convince me of economics as religion I agree with him on one major point: Economics, economic analysis is not value free. Economics is often more normative than we like to admit. Those presuppositions need to be examined. Luckily, they are.