The problem lies in the fact that soccer (or any other sport) is an entertainment and a display of sportsmanship.
If the World Cup soccer was a war, what they did to advance to the tournament would be a valid (although gambling) strategy.
But since it is not a war but a sport, I think it's only natural that such a strategy would be met with a scornful reaction.

That said, I agree that many of the same people in Japan who are scorning the coach now would have probably bitched just the same if they played normally and ended up with 0-2.
I personally can't really judge it because I didn't watch it. From what I hear, the coach and players themselves think it wasn't an admirable thing to do.