Epicurus never wrote that The Greatest Good is the Removal of Pain. He always identifies The Greatest Good as Pleasure. I think the concept of Removal of Pain is really only relevant with regards to the "limit" of Pleasure, and how to measure it. But anti-Pain is not the goal, just a measuring stick. Pleasure is the goal, and sometimes pain is necessary for a greater pleasure. Focusing on the Removal of Pain as a person's goal might lead them to miss out on rewarding challenges.
That's a very clear and simple way of stating it.
I continue to think that the background context which these "Pain-focused" people are missing is that the "limit" issue comes up in the specific context of the Platonic argument that "something which has no limit cannot be the greatest good, because it cannot be made better." Epicurus needed to establish a conceptual "limit of pleasure" and he did so very well, but he never intended that issue of a limit to overwrite everything else he ever wrote about "Pleasure" as we ordinarily feel and understand the word being the greatest good.
These guys are conflating "limit of pleasure" as if it were intended to denote some specific type of pleasure, so they run around in circles trying to equate "limit of pleasure" with ataraxia, aponia, kinetic, or katastematic pleasure. As I see it they are trying to define apples in terms of oranges and they will never get there with that approach. Worse, they make the entire issue hopelessly muddy. A two year old, or the proverbial newborn animals of any type, can simply by feeling run circles around that analysis, but these guys are hell-bent on pursuing it because it equates with their views of Stoicism and Buddhism.