The main thing that the original article is ignoring is the fact that the advertised EPA mileage for all cars (not just hybrids) is measured under idealized conditions that are not particularly close to real-world driving conditions, and the rated mileage for most cars, hybrid or not, is usually substantially greater than the mileage that the average driver will achieve.
For instance: I once owned a Saturn (non hybrid) that was rated for around 40 MPG (I can't remember the exact number, but it was definitely in the 35 to 40 MPG region). However, when new I believe my actual mileage was under 30 MPG and over the life of the car it drifted downwards until I was generally getting less than 25MPG.
My next car was a Prius that was rated 60 MPG highway and 66 MPG city (the only car I ever saw that had a higher mileage rated for city; that was second generation). I typically got 40 MPG. I was using it for relatively short trips, which is worst case for the Prius. When my wife took it on longer trips with mostly highway driving, she would get around 47 MPG.
The point is, I was satisfied because the mileage was far better than the Saturn, even though the Prius had a much larger and more comfortable interior. It fell below the rated mileage, but not really worse in this respect than the Saturn, proportionately speaking.
Some new hybrid owners get upset about the car not getting the rated mileage; many of these owners don't seem to have actually measured the mileage that they were getting in their previous non-hybrid car and just assume that it was getting its rated mileage. So they'll say "this car isn't getting any better mileage than my own car!" but they are invariably comparing apples to oranges: actual mileage of the hybrid vs. rated mileage of the old car.
I agree that TFA seems biased and not too well informed. I kind of doubt a class action suit on this basis would succeed.
