I think SCOTUS will "go with the flow" and agree with the majority of Circuit Courts of appeal. SCOTUS was invited in on all of the losses, and turned down the invitation. It's picking up the case where the Circuit Court found no constitutional right to homosexual marriage.
The article supposes that SCOTUS uses some legal principle to arrive at a conclusion, but it does the opposite. Conclusion comes first, then seeking out some legal principle that supposedly upholds that outcome.
That's my thinking too. The Justices who are determined to vote for this monstrosity probably already have their opinions written before they even looked at the arguments.