I'm not sure how you're getting "object-oriented programming" from this article, except that it was mentioned in passing as an example of a paradigm that belatedly entered mainstream software engineering. OOP is orthogonal to the comparison the article is making, which is between imperative and functional programming.

I found the (imperative : recipe :: functional : equation) analogy to be apt, especially for the lay audience. I agree that it may not be up to the task of contextualizing certain language features (like referential transparency; "the cook will always make the exact same cake if you give it the same stuff"), but like OOP, many of those features are not inherent to either of imperative or functional programming, and not important in understanding the difference.