"Where all are disqualified, none are disqualified"
Due process requires judicial disqualification in two circumstances:
where "a judge has a direct, personal, substantial, pecuniary interest” in a case" and
where "the probability of actual bias on the part of the judge or decisionmaker is too high to be constitutionally tolerable.”
Caperton v. A. T. Massey Coal Co., 556 U.S. 868 (2009).
There are also statutory disqualification requirements codified at 28 U.S.C. § 455, but none of them apply to this case.
While there can be reasonable debate over the meaningfulness of the conflict you've identified, it's hard to dispute that your premise would make judging virtually impossible.
Every justice on the Court holds copyrights, as does every judge in the appellate courts, every judge in the trial courts, and basically every person who has ever lived long enough to start drawing or writing. A rule that says "You can't decide copyright cases if you are a copyright holder" is a rule that says "No one can decide copyright cases."
And you could just as easily use this logic to disable a judge from handling virtually any kind of case. Can a justice decide a tax case if she has income? Can she decide an Establishment Clause case if she's a member of some religion? Can she decide property cases if she owns a house? Can she decide traffic cases if she drives a car? Can she decide Fourth Amendment cases if she doesn't like being spied on? Can she decide employment-law cases if her son has a job?
The further you go down that road, the clearer it becomes that you can't demand judicial disqualification simply because a judge has some indirect, theoretical interest in the outcome of a case, because one can always find such an interest for any judge, in any case. If we enforced the rule that way, there would be no one to decide any cases, and "there is a maxim of law to the effect that where all are disqualified, none are disqualified." Pilla v. Am. Bar Ass’n, 542 F.2d 56, 59 (8th Cir. 1976).
