I think there's a valid distinction you are making here, but only up to a point. Even among economists there are broad swaths of agreement, especially where microeconomics is concerned. For example, pretty much all economists agree that barring a small set of circumstances if the number of copies of an available good go down and demand remains the same, then the selling price of the good will go up. If anything, this situation seems similar, in that judges agree on the basics of statuotory interpretation even as there are very large ideological disagreements on other issues, such as how much weight (if any) to give to legislative statements of intent that are not part of a statute, or how to interpret constitutional questions. So the situations here may be pretty similar, and an appearance otherwise may be due to one simply knowing more about econ than legal issues. It would be very interesting to do a variant of this study where it is a constitutional rather than legislative question and see if that makes the judges more ideological. My guess is strongly that it will but that the judges will still be the least ideological weighted of any of the four groups.