This is not my area, so I'm only posting this because I think some answer is better than none at all.

It's because it's not law that the president or many other people are required to listen to the supreme court. Article 3 of the constitution, which sets up the judicial branch, is very vague about what that branch looks like, only saying that there is a supreme court, lower courts are allowed beneath that, and that there is a chief justice. Even outside the constitution, in the statutes and laws that have set up the judicial system, the supreme court is merely the highest official appeals court in the country; that is, it is the highest level of arbitration an appeal can reach, and it officially only has power over lower courts in the judicial system.

That's why the Marbury v Madison case is important historically- it set the precedent that the supreme court could rule on matters of constitutionality and have its opinion respected outside of the judicial branch. Still, there is no law that says that the judicial branch has any power over the executive, it's only precedent. Hence Jackson did nothing illegal in ignoring the court, and could not be impeached for breaking any law.

Someone far more knowledgeable about this than I can come in with a better answer and sources.