Yes, it was my post to which you are referring, and I was expecting to get push-back - the reason being the very reason for which I wrote it.
There are certain topics that operate a kind of "valve system" when it comes to criticism. One of these is weight, where it seems to be that people feel they are doing some sort of public honesty service by calling people out for being overweight, yet the merest hint that someone might look wrinkly or gaunt or ill from lack of weight is seen as rude (and it is). The same seems to apply to untidy houses where people love to critique from a position of thinking theirs is tidier (like the "friends" of the OP) as though being on the tidy side of the fence gives some sort of immunity to being unkind. Many such threads even start to haul out the MH diagnoses, and always judgments are cast such as @GethsemaneHall's comment that people with messy homes tend to "lack get up and go. " Yet try the accusations in reverse, and suddenly those types are 😦
The background to my post is that I mix with a lot of academics, and, you guessed it, many have faintly shambolic homes. I hear so much criticism of them for it. One had a party for her dc a couple of years back and the MIL was there. There are several tables in the house but, at that time, they were covered by paperwork and books (and yes, she has heard of bookcases, but was mid flight working on things). Her work was across two tables and a third had a huge and frankly rather amazing Lego work in progress that the whole family were doing together. But yes, it was messy. She had then organised a brilliant party game where she had set clay in trays with tiny fossils inside for the children to excavate. Of course that became a bit messy too and the amount of vitriolic criticism coming from her MIl was unbelievable. Lots of sneery muttering about "no wonder the place is such a shambles [tinkly, taut-throated laugh]"; "Well we COULD have put the cake on the table in the living room but ... " [ followed by despairing trailing off and pained look complete with eye roll]. And yes, the place was messy, probably shambolic, but the children were happy, stimulated and my dc have not stopped talking about that party. At that time I did think I have a mental image of EXACTLY what your house looks like MIL, and when we dropped by some months later it was indeed EXACTLY what I had imagined and I thought how absurd it would be if my friend had started in with the same sorts of negative, needling comments in the other direction. But of course she didn't, because in one direction commenting is seen by some as acceptable and in the other direction it is recognised as what it is: rude and judgy.
A similar story is possibly a bit outing so I paused before posting it, but then realised I need not worry as the friend in question has no DC, messy creatures that they are! But over the years I have got to know her DSis, who is a lovely lady. One of her DC is ND with SEN and she runs the most amazing art sessions for him and other children with similar needs. The house is quite messy, but she has loads of their work displayed everywhere and has put a lot of time into it generally. My friend herself, who is fun on a night out but frankly lives in quite a self-focused way, is unbelievably condescending about her Dsis' home. She herself has loads of (honestly quite amazing; I think they both have an artistic vibe that self-expresses very differently) wardrobe of incredible clothes. Think big walk-in with a glass centre cabinet to keep dust of her gloves etc. But she thinks it is somehow fine to talk about her Dsis as having "a grotty little house with all that peculiar kiddy craft everywhere." I just don't think it's OK, and I do tire of hearing these things dressed up as "concerns" for people.
Both the messy home owners in these examples have nothing whatsoever to feel embarrassed about, and both bring a lot of joy and skill to bear on their activities.
So I'm afraid I take the view that if it's ok to cast judgment, then it can be cast in all directions. We can all say what we think when we enter a certain type of home. Or we all shut up: I don't mind which.
And I'm glad some poster's reactions demonstrate they have clearly taken heart in what I posted.
And as for the comments about jealousy, yes I think that DOES play a role, but usually not on the part of the person with the mess. I suspect my friend's MIL is a frustrated academic herself who never got the chance and would have loved to get her teeth into something a bit more fulfilling than pledging the dining room table for the 8th time that month.
As for me, I'm lucky: we have a cleaner - as does, incidentally, the friend with the enormous, glass-cabinted dressing room. But I am not about to judge anyone who doesn't.