I did find the article’s point - that having a comically evil villain can sometimes work out really well as a narrative device - to be relevant. The example that the author points out - that some people are just plain evil and their malice is beyond comprehension - is exhibited really well by the Joker. A few other memorable examples that come to mind where such villainy plays off its absurdity to make a larger point are Gary Oldman in Leon the Professional and Tilda Swinton’s various villains in Joon-ho’s films.

But far too often the one dimensionality is used as a lazy writing device and serves as a showcase for an amateurish script.

I think really good villains tend to have a traumatic/motivational background that guides their desires but also fundamental personality flaws that lead to them acting well outside the bounds of normal human behavior. Some modern stories fall down when they decide to just take forever really grinding that explanation into the audience. For example, Ramsay Bolton was a great modern villain. I don't need to spend an hour watching him be sad that his dad was mean to him.

I think the differentiator is the quality of “evil” — the joker has a type of evil, with a certain texture and patterns associated with it. Whereas a truly 1D villain will simply take on any kind of evil necessary to fit the moral goal. You don’t need to provide a reason behind it, but you still need an internal consistency, which boring characters generally lack. It should feel like there is a driver, even if you don’t know what it is.