The writers of the law clearly wanted to establish state exchanges for any state that wanted them, and a federal exchange for any state that didn't want to roll its own, and that all of these exchanges do the same thing.
Never mind the fact that Gruber said explicitly that the point of not offering subsidy money to residents of states w/o an exchange was to coerce the states into created the exchanges.
A slippery slope indeed when the judicial branch interprets laws intent rather than the words written. But did we really expect they would force the federal government to stop providing bread and circuses to the plebs?
Back in my day we used to say "If it smells like cologne, leave it alone, if it smells like fish, make it a dish". Now get off my lawn with your fancy schmancy color changing condoms!