"Is it significant?"
Of course! The fact that a gay man is a judge at this level is significant. Was there a Black judge in a position of similar stature in VA "back then"? Kinda doubt it! I The fact that the California judicial system did not "organize" a gay judge out of presiding over this case is significant. All of that speaks volumes about the progress made to date by LGBT citizens.

"Should it matter?"
Fuck no! One way or another,t he judge in this case is going to be on one side or another. Would anybody raise an eyebrow if the judge were straight? Fuck no! So, STFU about the implications of the judge being gay. Unless he's getting a Monica under his robe while presiding, his sexual preference is not relevant.

"Can he be objective?
A much so as any judge can be. We believe judges honor their commitment to be impartial. Unless you are a paranoid, homophobic, Bible-banging, pulpit-pounding right-winger, you should have no more reason to worry about a gay judge than a straight judge.

"Will his sexual orientation matter in an appellate court?"
It should not. Given the individuals who are the plaintiff's counsel, I have faith they will be able to shoot holes in an effort to raise the fact as an issue. What I don't know is if the appellate court will be objective or if it will have a latent anti-gay predisposition . . . or be populated by Alito-Scalia-Thomas wanna-bees.

Does it matter? What's your question? Please be more specific.