Maybe I’m confused what you mean. Being opposed to the concept of laws doesn’t mean you need to break them; you can still think “people shouldn’t murder” or “slavery is bad”. I don’t think incidentally following laws makes you not Chaotic. You just don’t care what the law is; you’d be doing the same thing regardless of whether it was the law or not.
Besides, I’m not sure “opposed to the concept of laws” is really true for all but the most extreme examples of CG. It seems like its more about wanting freedom than just hating laws themselves.
I agree that chaotic characters would be more inclined to break laws. But I suppose to circle back, I don’t see why that makes them any less Good.
Even your description of “law is an impediment to justice” sounds like a CG character would just do whatever they want without letting laws stop them, while NG might be more likely to consider whether or not to follow the law in any given circumstance and perhaps adjust their plan to be slightly more lawful, while CG might not respect the rule of law at all and just break into the prison and free the slaves or whatever.
Side note: I agree that law and freedom aren’t necessarily in opposition as pure concepts. But part of my argument is that CG characters wouldn’t innately hate objectively good laws like “don’t keep slaves”. The laws they’d take issue with are ones that limit freedom, like “don’t steal”. Most probably wouldn’t be ideologues campaigning for the destruction of the government but they might just steal to fund their Good.