You raise a very good counter to what feels like the main thrust of the guys article. It put to words something that felt "off" to me while reading it, that there was an assumption made that was never stated and was also incorrect - so thanks for putting that to words.
He seems to assume that there is 1 air fryer that everyone on Earth should be getting, and all others are strictly inferior. There are probably no products that exists where that logic is true. There is so much variation in cost vs quality, or entire feature-sets like you pointed out.
This bleeds over into incredibly "messy" areas too, like societal signaling. Someone might specifically want a more expensive version of something simply because it's more expensive. The author doesn't seem to account for any of this complexity, even the "simple" complexity of cost/quality/features.
The value that these types of ads can add is that Amazon can build up models that can "learn" and get better at matching every unique persons criteria and provide a way for vendors to get "matched" with that buyer. Obviously you can still critique this model, but to assume it's strictly bad feels like it lacks nuance/critical thinking.
I think the idea is true if you reverse it: there are a lot of cheap air fryers that are not worth buying over a one or more "good value" alternatives.
This also lines up a lot better with other complaints with amazon: their inability to get rid of counterfeit sellers, the degree to which their reviews (and listings) are gamed, etc. Arguably the reason people buy garbage on Amazon has more to do with their lack of interest in policing misbehavior than ads (though perhaps the ads are the financial incentive to keep being lazy).
You can see this with the knockoff[1] plugin that flags "no-name" brands on amazon. Sometimes this takes out the listings you want and you need to consider it, but I think it's a pretty effective counter to the kinds of scammy ads this poster is frustrated with.
I don't think that nuance changes the big picture which is that Amazon has a conflict of interest between showing you the best product that you want, and showing you the product that the seller is most willing to pay to advertise. Quibbling over nuance just gives air cover to this fundamentally extractive rent seeking behavior. We really need stronger anti-trust action in the tech era given the extremely low friction and winner-takes-all dynamics of modern tech economy.