You’re conflating two different things. In the former, states have set up legal framework for marijuana sales. In the later, state laws don’t have any opinion on the matter.
If a state like California sets up an imprisonment scheme under it's laws that violates federal law (to choose an example that has happened recently), it's still illegal prison overcrowding, not legal prison overcrowding.
A system under state law in violation of valid federal law is, because of the supremacy clause, an illegal system.
A system under state law in violation of valid federal law is, because of the supremacy clause, an illegal system.