Roberts is just as vile as any one of the Three Stooges, but a tad slier. He knows that in order to implement the Right Wings' "only the little people pay taxes" strategy effectively, the implementers, i.e. The Supremes, must not be seen to do so obviously. This case could, and should, have been tossed on lack of standing grounds, since the complainant wasn't, and isn't, affected by the ACA. But that would have dragged things out a bit longer. Whether the Right Wing could have found a redneck with standing, is an open issue.
Once it was clear that 5 would deny, it costs him nothing to be the 6th. He gets to play grown-up amongst the juveniles. His original ruling is a bit murkier, given the vote. Nonetheless, Roberts hasn't morphed into a compassionate conservative. Reporting leading up to the decision made clear that work-arounds had already been developed to the exchange problem, anyway. Even if Roberts could have been the 5th against, it wouldn't have done the job of the Right Wing, killing ACA.
Linda Greenhouse is the NYT court reporter, and her take is worth a read. She doesn't see the cynicism as I do. One can't have everything.
But what would be truly indefensible, I believe the chief justice and Justice Kennedy came to understand, was the Supreme Court itself, if it bought a cynically manufactured and meritless argument and thus came to be perceived as a partisan tool.
Next time, subtlety.
I was off-line today until I submitted this in its various places. So the news on marriage just found me. All I can say, re:Roberts, is QED.