When there was a tackle and it looked liked someone might have faked and dived, replay didn't come. When it actually hit someone, then there was a replay showing that. Same happened with offsides. If there was an offside which wasn't blown, there wasn't a replay. For correct calls replay was always shown. And this list extends to playing with hand, tearing and corner and free kick hassles.
Someone in Fifa might have had the idea, that people are so stupid, that if we don't show the replay they don't notice there was an error. They hugely underestimate capabilities of football fans. Referee errors are part of the game and all possible replays should be shown. That's part of the excitement.
Biggest problem with this decision is that now the Oscar nominees of football will not be exposed to viewers. Fifa decided to reward the guys who can trick the referees the most. Only real way forward would be to show all the acted stuff happening in the field and let people to judge those. No one really likes those actors and if football fans would really properly see who are the worst actors in the field, they would start to hate those. That would eventually start to affect to the game. Take Premier league as an example, there those guys who fall too easily are not appreciated at all and there you don't see that much acted falls.
Best what Fifa could now do would be that they would make statistics with videos of referee errors and faked falls and let the people to learn and judge themselves. Organisation as flexible as Fifa, I don't really believe this happening.