Well that's not true.
If you read the current court's opinions they have precedents at the core of most of their arguments. It's precedent after precedent in their conclusions.
As for 6-3, the reason it wasn't 9-0 is because three justices pointed out that there wasn't a live controversy that could be addressed:
"In short, this case is over, and petitioners won. The trial court’s original final judgment in favor of petitioners, affirmed by the State Supreme Court in Harper III, represents “the final determination of the rights of the parties” in this case. [...] As a result, petitioners’ alternative Elections Clause defense to those claims no longer requires decision; the merits of that defense simply have no bearing on the judgment between the parties in this action. That is the definition of mootness for an issue."
