"It's telling that the automakers have chosen to cheat rather than call out the tests for being unrealistic"
They do that, too. You can probably imagine the response the HN crowd would give, which is pretty much the same response the news media would spin it with... money-grubbing rich companies trying to escape from beneficent, unambiguously good laws so they can make more dirty, polluting money. It doesn't play well, so they don't make this argument in public. But if you live in Michigan, you can find plenty of engineers who grouse about the standards in various ways, and not just "they're hard". (Believe it or not, engineers have families too, and like them and their families to not die in the cars they quite likely drive themselves.)
Between the media's drive to drum up antipathy towards the automotive companies for both their own ideological reasons and simply because stories about big corrupt companies sell, and the ever-present and unavoidable politics (of all kinds) involved in any sort of standards setting, there's so much noise that on those occasions where literally impossible regulations are created, the system is not very good at dealing with it. I am speaking neutrally here, because in the real world, balancing between costs and benefits of regulations is a very hard problem and I'm not really yelling at any particular party here for not getting it perfect. It's a systemic problem.
I rather strongly suspect that if we could get a perfect judge that the current set of regulations is probably already impossible to comply with at all; failing that it probably can't be complied with economically. I seriously doubt emissions are the only problems, they're just the ones people are motivated to test. I bet if Consumer's Reports or a similar organization set up a full legal compliance suite they couldn't buy a single car from a dealership lot that complied completely with everything. I think they'd be close on most measurements. But I bet every vehicle would fail something, and there'd be a non-trivial number of rather substantial failures.
(For an example of the latter, noise regulations on how loud cars can be as they pass you at various speeds are really easy to fail on a specific car. A particular bit of trim that came loose during shipping or something can fail you out very easily. Now, this one is less important in the grand scheme of things than emissions, but it's an example of a regulation that could pass at the test site but fail on many or even most cars in the field.)