The law stipulates that she must. Congress directed that federal judicial officers must disqualify themselves from hearing cases in specified circumstances.
Title 28, Section 455 of the United States Code states, "any justice, judge, or magistrate judge of the United States shall disqualify himself in any proceeding in which his impartiality might reasonably be questioned."
Legally, she's supposed to recuse herself from this case. I would argue so is Kagan who's been out performing homosexual weddings.
The problem, of course, is that the people in power now on the left are amoral/immoral conventionalists who sincerely believe that the end justifies the means and that immoralities slated for implementation on their leftist social agenda are fully equitable with actual morality and they are willing to disregard the rule of law to accomplish their objectives.
These people are "anti-Christ" in their beliefs and practices. Correlations between the wicked rulers of ancient Israel can be made.
Agree with your post that's why it's so shocking that one of these lawless people would recuse herself!