The fact that other refs may have failed to act when they should, does not mean this ref was wrong. I'll reiterate what I've said before, if worse fouls than this were committed, I certainly think they ought to have given straight reds also. But lets face it, sometimes a ref either doesn't see it, sees it from a bad angle, is afraid of being/looking biased if he has made a lot of calls against the team already, or hell in some cases I think they just don't have the guts to send a man off.
This ref just happened to have a perfect view to the foul, from just 15 feet away, and he was not afraid to call it as he saw it. Right or wrong, it's done. And the US still has a decent chance for advancement - If Italy beat the Czechs (which seems likely), and the US beats Ghana, that will do it.