I believe that corruption in FIFA most often manifests itself in the selection of tournament host countries or in the sale of exclusive television rights. Frankly, I don't believe that FIFA's leadership advises individual referees on their work. 🙋
Referees are human. Like everyone else, they are subject to fears... In my country, an aggressive slogan is popular among football fans: "Turn the referee into soap" (unfortunately, there are many ultras among football fans). It's not surprising that referees are afraid to penalize star players. They fear aggression from fans. In my opinion, this is why we saw lenient refereeing towards Messi and other Argentine players. As for Ronaldo, I believe his punishment was typical of this type of violation.
FIFA is made up of sports officials, and officials are generally unpopular. However, I think most of the accusations against them are more conspiracy theories than real accusations. For example, I don't believe they have any influence on the draw and the distribution of football teams into groups. Football is simply about strong emotions! That's why so many conspiracy theories arise around it.💁
This is very much correct, and those that claim that there is some institutional favouritism all the way down to the bottom of the chain that is the referees do not have data that confirm this and they do not even know how cover ups work. The data on FIFA corruption is clear, it is mostly concentrated to the top and is about some of the things that you have written here. This works because it is concentrated in a few people who have the power and can make those decisions effectively and keep most of the information and deals secret most of the time. When you think how many referees have participated over the years and if you know how coverups work one would easily realize that this would never work. Someone would tell someone else that they should not and it would start leaking from sources close to those that are involved, that is always what happens when many people are involved. That is why this is impossible, so either real proof would come to light or it is not a thing.