“They might not have rejected him, but probably would express doubts on specific practices. That would even more likely be the case if he benefited personally from such practices.”
Well since his job was Commissioner of Customs for Scotland, I think he did benefit personally:
http://www.econlib.org/library/YPDBooks/Rae/raeLS20.html
While one might favor what is best for society, one must live in the society as it actually is.