It being in the legal realm probably had some impact. These tools can be seen as an attack on your profession, and I’m sure that affects the decision, whether conscious or not.
The judge is a user of Westlaw and not a shareholder, as is the judge's office. They would like Westlaw to be cheaper and easier to use. Westlaw takes the judge's work product and profits from it. Arguably, Westlaw should demand all judges recuse themselves!