http://www.futilitycloset.com/2010/06/09/intercepted/

This isn't so much a puzzle as a conundrum. Perhaps there is an official stance on the matter, I dunno...

agree; after d5 white is check-mated, end of game.

The first two claims of checkmate are incorrect -- there is no "matter of opinion", as 1. … d5 never was checkmate since 2. cxd6 e.p. is a valid defense.  The logistics behind what en passant represents is irrelevant -- the legality of the move transcends the technicality raised by Black.

Except 2.cxd6 e.p. does not stop the attack on the White King!

Oh, my mistake, I need to read more closely.

Black clearly wins here.  cxd6 e.p. follows a legal move that blocked the check -- again, the logistics behind what en passant represents is irrelevant -- black moved that pawn to d5, blocking the check, and it was subsequently captured on d6 for checkmate.

Black mates.

2. cxd6 e.p. will never be played because the game is already over, that is (I think) what SensFan33 is saying.

I certainly agree that the matter is not a matter of opinion ;-)

 yup

White's wrong, and an idiot, but might make a good layer.

The EP is a move by white. He can't move a piece while in check unless it gets him out of check. This move clearly does not get him out of check, it only puts his opponent into check, so it is invalid.

You could construct a similar board and reasoning without the en passant but using other pieces and black would still win. The EP is a red herring in that article.