Well, I am not about to split hairs with someone with 36 years in flooring, - too much respect. But I work in the water damage industry so have also seen first-hand the effect of water on carpet.
And I will point out that only the lesser quality latexes can and will break down and delaminate a carpet (oftentimes the characteristic fishy smell accompanies this process, known as "Indian Rubber"). Most prevalent in area rugs and so-called orientals, but the principle is the same.
In these cases I will agree with you and say that the latex used is I guess, "water-soluble" (actually water-reemulsifiable) and will break down into it's components. Same thing happens with tile mastics upon wetting because there they use a different polymer based on polyvinyl acetate since it is not really meant to be water-resistant. Same resin used in cheaper carpet adhesives - but the better adhesives have to be water-resistant because of the cleaning processes (most manufacturers recommend steam cleaning) and therefore the adhesive technology is different. These adhesives are only water-based, but far less water-soluble, if at all.
Admittedly, if soaked for 24 hours, there is a good chance you will witness carpet delamination - but my point is that that circumstance alone is no reason to dissuade people from steam cleaning their wall-to-wall carpeting.
Similarly, I have seen carpet delaminate by urine overdoses, but that's a pH and microbial action-derived delamination due in part due to the lack of antimicrobials in the latex formulation, not just because it was wet but I take your point. I'll add solvent overuse to the mix too, but not a valid reason IMO to shun steam cleaning...
Finally, I think delamination and shrinkage are very minor 'negatives' amongst the 'positives' that good carpet cleaning can bring.
Personally I encourage people to clean their carpets more often than perhaps they already do. :yes: