Well it's pretty easy to take the moral high ground now, some would look rather silly if they started talking about refs after all.
The fact of the World Cup is that referees are from all corners of the world, some are clearly going to be officiating at a very poor level of football in their domestic leagues and not up to the job of refereeing at this level. Throw in the factor that these referees will all have their own styles and perceptions, many don't even follow basic FIFA guidelines, others toe the line to an absurd degree like robots.
You can't legitimately say that referees are throwing a game because FIFA told them to, I don't think that has happened since the 1970's (even Havelange admitted it, and he would know a thing or two about it), there is no proof of that. What FIFA can do is put referees into a game who are likely to officiate in a certain way, to create a complete randomness to the game. Most of it just comes down to the individual. We will never know what the motivation behind guys like Moreno was, perhaps someone was paying him, perhaps he started to side with Korea like many neutrals, perhaps he was just downright awful, but then when the Spain game came round it starts to look extremely suspicious off the back of an already horrible match. People will say that good teams should be able to play and win in spite of the ref, but they shouldn't have to. Why should people accept mediocrity at World Cup level?
Generally I think referees have been fine at this World Cup, although I think a lot of that was down to the placid nature of the first group matches. There was not a lot for them to call in so many defensive matches, not many controversies to create, aside from the Cahill red and a few minor calls. Now we are getting into the nitty gritty part of the groups it starts getting difficult for them, they need to be good enough to make basic decisions like the one today.