They shouldn't. I'm not saying that Git doesn't have commands that can be hard to understand fully, but the whole point of any abstraction is to hide the "insides" of any operation so you don't have to think about them.
Having commands for each DAG operation will just add more complexity and expose a structure which you shouldn't be handling manually.
Having commands for each DAG operation will just add more complexity and expose a structure which you shouldn't be handling manually.