On a note about South Korea, there were several controversial decisions which went their way during the World Cup. That, however, is a factor in the run of many teams who advance far in the tournament.
In truth, the "cheating" accusations came from several top footballing nations, whose teams performed poorly in the tournament. I seem to recall several of the traditional favorites failed to get out of the group stage. Those nations were arrogant, and thought other teams should roll over and give up just because of their reputations.