I would agree with you that Santinelli didn't object to transfusion for the same doctrinal reason that Watchtower objects. However, they made no such argument in the brief. All they do is say that experimental transfusions were underway in the 17th century, accurately quote a portion of what Santinelli wrote, and move on. You observe that:
" everything argued by Watchtower is in support of the organization’s unique theology objecting to blood transfusion and 'the adventures and misadventures of transfusion practice in modern times.' Santinelli’s view neither supports the unique theology of Watchtower nor addresses blood transfusion as practiced in modern times."
This is true. But they don't argue anywhere in the brief that Santinelli's view supports their theology. You might make the implication, but they didn't say it. I don't even think they imply it. Santinelli's name is not mentioned in the brief anywhere after this quote. I understand your point, but realistically you could find worse than this in almost any appellate brief in any case around the country. That's why both sides have lawyers; to point out the weaknesses in the other side's argument and to present the facts in the most favorable light for the client.