I love the bingo card of responses - so spot on!
I often wonder what I'd do if I was in a relationship. The nearest I get is when my DDad comes to visit (usually for a week or two at a time): we have a split where I cook and he washes up (and quite frequently peels veg). Now sometimes it isn't brilliant - but the thing is, in his case I know it's not because he's being half arsed about it, it's because he quite literally doesn't see the dirt - because he's 74 and his eyesight is going! And (equally importantly) when I re-wash something he just says "oops, sorry, missed a bit", doesn't try to pretend it was alright in the first place or that my standards are crazily high. As you say, a rational person accepts that a dish is either washed properly or it isn't - it can't be a little bit washed.
So it's (what seems to me at any rate - apologies if I've got your post wrong) your husband's immediate response of "deny, shift blame" that would piss me off, I think. And I honestly don't know what I'd do. Now I'm a crusty old bat in my late forties, if I ever got into a live in relationship, I'd call them on it very first time it happened. But I know that back in my twenties and thirties, I wouldn't have had the nouse to spot what was happening right from the outset - I'd have known that it pissed me off, but not been able to articulate why it was so annoying, and I'd have known that using the word "nag" in response to any attempt to get them to do it better would send my blood pressure through the roof, but again, not precisely why. And then, by the time I could see exactly why it was so bloody annoying, the behaviours would be so entrenched that I couldn't call them on it.
I think now, from my crusty old bat (COB - could that be a good acronym) perspective, the conversation might go: first piece of bad washing up, polite request to redo it nicely with reminded that not only am I not there to do all the washing up, I am not there to be quality control manager either. Any attempt to dodge blame (ooh, I'm not good at doing dishes, ooh, I was going to do them properly, but just needed to watch XYZ on telly first) would be met with "imagine a colleague tried to use this sort of excuse to avoid doing stuff." Any use of the word "nag" would lead to a feminist discussion of the misogynist overtones of the word "nag". Further argument would lead to them being introduced to the front door. But that's only because I've read a lot of Mumsnet and watched a lot of friends' partners shirking domestic jobs (I also have a lot of friends in fabulous relationships who've modelled how things should be). As I say, back in my twenties and thirties I wouldn't have been able to see the "strategic incompetence", "gaslighting", "blame-shifting" and use of the "N" word for the bullshit they were.