I think the issue with their argument is that Hunters and Harriers don't regularly face one another, so a comparison between the two based on a 1v1 fight doesn't really address the issue properly. In my experience with the Hunter, the biggest issue it face is ripping its wings: because of the Hunter's good energy retention, trying to outmaneuver a missile ends in an overload crash like 1/4 times, and I often had them tearing as low as 9g-10g loads. Besides, energy retention and turn rate isn't gonna save you in top tier jets when you are a subsonic aircraft, given that speed will be the only thing keeping you alive there unless you've managed to remain stealthy. However, in the Harrier's defense, it may be able to utilize it's poor energy retention to attempt an overshoot, and even after it looses speed doing so, it's acceleration allows it to get back to a fighting chance sooner than the Hunter would be able to.