Similarly stemming from "the antagonist must be bad" line of thinking, this article also fails to properly address that a story can have a "bad" character, a villain, who isn't the story's antagonist at all. A villain is a type of character, while an antagonist is a role in the narrative.

Failing to grasp that is something that I think gets in the way of a lot of beginner writers. They believe that by putting a villain in the story, they've made an antagonist, because it's a bad guy, duh, but if the villain doesn't actually contribute to conflict in the plot that gets in the hero's way of achieving their goal, they aren't an antagonist.

While this is helpful from an archetypal standpoint, putting "antagonist" in the title is somewhat misleading, because writing an antagonist has a lot more to do with understanding narrative structure, and how the component parts of a story feed into one another, than character archetypes. Doing bad things does not an antagonist make, and writing a character that does bad things is not the same as writing conflict.