Well, it was a desperate act, certainly unsportsmanlike, which is why he was sent off and Ghana was awarded a penalty. The circumstances were extreme - last kick of the game - but there's really no way to argue that Suarez 'should' have kept his arms down for sportsmanlike reasons. "Oh well, we lost, but at least we did the right thing there at the end." He did what he did and was sent off for it. And it was probably more of a reflex than a conscious decision anyway.
To argue that it was a conscious effort by Uruguay to manipulate the rules seems absurd to me - Gyan had scored two penalties in the tournament prior to this last-second one, so the odds were clearly in Ghana's favor to score and win the match. But alas, he missed. And the shoot-outs went Uruguay's way too.
Great match. Uruguay will be severly handicapped in the semi though (possibly against Spain) (EDIT: they're facing Holland, obviously). Both Lugano (the captain, out with injury) and Suarez are out, and possibly more - didn't notice if anyone got a yellow card which will rule them out of the next match.