Unless I didn't understand the situation, these "wealthy" visas are the law.

Rule of law doesn't mean the law can't make a difference between the rich and the poor, in fact, it is very common in tax law (the rich pay more taxes), but not only.

Rule of law just means "no corruption", essentially. That the laws are the only criteria for judging people, it is not a discussion about the fairness of the law itself. It there is a "no parking" sign, then under the rule of law, no one will be allowed to park, including Bob, who will be fined/towed like everyone else. But if the sign says "no parking, except for Bob", then Bob will be allowed to park even if people find it unfair.

Usually, high rule of law countries are also democracies, so laws are made by elected officials, or even directly by people, and fairness is an important part of the lawmaking process. Indeed, people are usually reticent to apply laws they feel unfair, but technically, rule of law can apply even in the most unfair, despotic systems.