Fair enough alright.
I'm assuming you want to know why the heroes should be considered "good" and why villains should be considered "bad". (correct me if I've misrepresented you)
I would say in the lawless situation in OfA time, AfO's ways maybe considered "good enough" for the simply lack of better alternatives. It begs the question of whether the "better" should be abandoned for the "good" just because something works - but that'll take all day. I think AfO sums the difficulty pretty well when he reproached his brother for having no power to exercise his ideals
In the stable society of present day MHA universe though, what AfO does is at best vigilantism, and at worst gangsterism. Neither of which confers net good to society