And for the point, I've worked with Ekman. This sub-field is not scientifically possible.
Not denying the snake oil currently in the sector as a whole, but I think the tech should eventually be able to do anything our minds can do.
It would be fraud if and only if it's no better than chance, if it has no correlation whatsoever with the true emotional state - and it's perfectly possible (by both humans and machines) to make an "educated guess" about the emotional state that would - especially in agregate for many humans - be informative for all kinds of purposes, even if it can be easily cheated by a professional actor. For example, you probably can detect if a particular section of an online class turns people unusually frustrated or unusually sleepy, even if it doesn't affect all people, half of affected people don't show it or aren't detected, and there's a professional actor in the class faking the exactly opposite signal. Also, there are many scenarios where it's not even worth considering antagonistic behavior, where people have no motivation to put any effort in misleading it.
The argument that it's impossible to determine the inner state of an individual with certainty is irrelevant, because noone is claiming that, and it's not a requirement for the described use cases. After all, surveys of "do you like product/person X" provide valuable information even if it's trivial for anyone surveyed to lie. All the system needs to do (which needs to be properly validated, of course) is to provide some metric that in practice turns out to be reasonably correlated with the inner state of the individual, even if it doesn't work in all cases and for all individuals, and that IMHO is definitely achievable.
Perhaps it's more a difference in semantics - what do we call if a system (or human) for identifying some status or truth is halfway between "no better than chance" and "can identify the true status 100% of the time". I would say that it's a feasible system for identifying that thing, and that system works (though it's not perfect); it seems that you would say that such a system does not work - but how would you call or describe such a halfway-accurate system?
Do you really not think it's possible to read emotions from facial expressions? If humans can do it, a machine can do it better. The claim from the article that machines can't read emotions is pure motivated reasoning so distorted and disconnected from reality that it amounts to fraud. It's obviously the case that faces convey emotions. Look around.
Facial expressions are a terrible indication of emotional state because humans are multi-layered: what's to say the person with a grimace does not have a tooth ache, or a bad back - yet otherwise is in completely normal state for them, if asked they'd say they are good.
I perceive the majority of people considering this situation to only be considering 1st level effects. I have seriously considered this as a professional ambition, scientifically investigated the situation and discarded the concept as unreliable at best and a fraud engine in reality.
Think about this a bit more, use your scientific method training. you'll come to the conclusion this is not science, this is pseudo-science and fraud.