I'm really less surprised by the writer's opinion than by his admiration for Justice Kennedy's prose. I wouldn't go as far as the person who said the ruling sounded like something a 17-year-old would post on Facebook, but on the basis of this sample (I haven't read the whole thing) I'd call it pretty ordinary stuff. There's a distinctly pompous note there, never mind the jarring dissonance of his application of the term "marital union." Surely Kennedy, like most judges who have opined on this subject, is hearing in his mind's ear the praise which he expects future historians to lavish on his edicts. And notice the "I have spoken" tone of that last sentence. A majority of the justices, and a majority of liberals, now seem to think of the Supreme Court as a council of elders with the power to make decisions for the whole tribe on the basis of their own unaided wisdom.
Perhaps the jarring dissonance is only a result of my conditioning, my prejudices, my inability to change. I can see already that it's going to be a bit of a struggle at times to hold out against this soothing spell. One may have to be willing to stick one's foot into the fire, like Puddleglum in The Silver Chair.
NB: I realize the Image piece is just a post at the magazine's blog, but I see no reason to think the editors would disagree.