Maybe so but the whole system of appeals is supposed to overturn judges who are egregiously off-base. That didn't work in this case and you can conjecture all sorts of reasons why. We know there are people who look at someone in Terri's situation and say, "Hey, I wouldn't want to have to take care of her." Or, "I wouldn't want to live like that." And some of those people are judges. It'd be naive to think judges interpret the law without bringing their own personal bias to the table. Happens all the time.
Unfortunately, appeals courts are generally not allowed to question judicial findings of fact. If a judge makes a declaration of fact and says he examined all the evidence, then even if 99.44% of the evidence contradicts the judge's finding, it shall nonetheless be beyond question.
Although there are reasons why judge's findings should not be routinely questioned, the appeals court system provides no protection against judges whose findings are just plain wrong. Worse, laws which are supposed to prevent people from "judge shopping" instead mean that someone who gets hoodwinked into accepting a bad judge will be unable to escape his power.