No, it isn't disingenuous, and it is an airline problem. just because someone has been boiled slowly to accept the theft in volumetrics, doesn't mean it's not objectively unworkable for 3 male US adults to sit across three 16 inch width seats with a single armrest separator already thinner than a human female upper arm with the minimum anatomically required presence of muscle and tendons. The pitch issue is often talked more, in my opinion too much for distracting effect. But it's seat width where the real theft in long duration seating tolerance has occurred.
It's easy to handwave it away as a fat people complaint but it has nothing with fat people. Load factors are higher now, and seats on a volumetrics more expensive, not less.
Yes, that indignity works when you're trying to cross the planet in 24 hours, but for domestic hops that could be done by a train (well, if the country's rail infrastructure didn't stink of regulatory capture and public carriage disinvestment), no way. Not for 500-800+ round trip it doesn't.
In 1985 no seats in US4 were narrower than 19 inches. Today some seats in united's domestic offering are as narrow as 16 inches. And remember, people were thinner in 1985, and load factors were lower. Ergo it's an airline causation, not consumer health causation. 1985 was post deregulation as well, so don't give me the "those tickets were 3k inflation adjusted", they simply weren't. Some people are still able to remember pre 197x airline pricing. Deregulation was either cheaper or more expensive, it can't be both to suit an argument of consumer-blaming.