They want this to be up to the states. Federal legislation encroaches on the "laboratories of democracy".

Well since there is no federal statute on it, and the Constitution doesn't assign it to the federal government, it goes back to the states. That's how everything works, by default.

There's nothing in the ruling that I'm aware of that would prevent Congress from passing a law on it. But I haven't read the whole ruling, and I'm certainly not an expert. So I'm open to being shown otherwise.

Any legislation passed by congress will get challenged by the states that want to restrict abortion. This court will side with the state challenging the federal law.