Also, legality isn't the only difference in the VW case. With VW, they had a "good emissions" mode. They enabled the good emissions mode during the test, but disabled it during regular driving. It would have worked during regular driving, but they disabled it during regular driving. With compilers, there's no "good performance" mode that would work during regular usage that they're disabling during regular usage.
It sounds like a mismatch of definition, but I doubt you're ambivalent about a behavior right until the moment it becomes illegal, after which you think it unethical. Law is the codification and enforcement of a social contract, not the creation of it.
There are many cases where I think that. Examples:
* Underage drinking. If it's legal for someone to drink, I think it's in general ethical. If it's illegal, I think it's in general unethical.
* Tax avoidance strategies. If the IRS says a strategy is allowed, I think it's ethical. If the IRS says a strategy is not allowed, I think it's unethical.
* Right on red. If the government says right on red is allowed, I think it's ethical. If the government (e.g. NYC) says right on red is not allowed, I think it's unethical.
The VW case was emissions regulations. I think they have an ethical obligation to obey emissions regulations. In the absence of regulations, it's not an obvious ethical problem to prioritize fuel efficiency instead of emissions (that's I believe what VW was doing).
You might consider disregarding the government’s preventative measures unethical, and doing those things might be the way someone disregards the governments protective guidelines, but that doesn’t make those actions unethical any more than governments explicitly legalizing something makes it ethical.
To use a clearer example, the ethicality of abortion— regardless of what you think of it— is not changed by its legal status. You might consider violating the law unethical, so breaking abortion laws would constitute the same ethical violation as underage drinking, but those laws don’t change the ethics of abortion itself. People who consider it unethical still consider it unethical where it’s legal, and those that consider it ethical still consider it ethical where it’s not legal.
Abortion opponents view it as killing an innocent person. So that's unethical regardless of whether it's legal. I'm not contesting in any way that legal things can be unethical. Abortion supporters view it as a human right, and that right is more important than the law.
Right on red, underage drinking, and increasing car emissions aren't human rights. So outside of extenuating circumstances, if they're illegal, I see them as unethical.
So it doesn't matter that a very small percentage of the world's population believes life begins at conception, it's still unethical? Or is everything unethical that anyone thinks is unethical across the board, regardless of the other factors? Since some vegans believe eating honey is unethical, does that mean it's unethical for everybody, or would it only be unethical if it was illegal?
In autocracies where all newly married couples were legally compelled to allow the local lord to rape the bride before they consummated the marriage, avoiding that would be unethical?
Were the sit-in protest of the American civil rights era unethical? They were illegal.
Was it unethical to hide people from the Nazis when they were search for people to exterminate? It was against the law.
Was apartheid ethical? It was the law.
Was slavery ethical? It was the law.
Were the jim crow laws ethical?
I have to say, I just fundamentally don't understand your faith in the infallibility of humanity's leaders and governing structures. Do I think it's generally a good idea to follow the law? Of course. But there are so very many laws that are clearly unethical. I think your conflating legal correctness with mores with core foundational ethics is rather strange.