It should be noted that Alan Kay invented the Smalltalk-72 language, which is very different from the Smalltalk-76 and onward versions of the language, which were rather invented by Dan Ingalls. The quote applies to Kay's vision of OO, which is much closer to Smalltalk-72 than any other OO language. Smalltalk-76 onwards instead are closer to the concepts invented in 1967 for the Simula language. Also note that the first documented application of the term "object-oriented" for a programming language was in the 1976 publication by Jones and Liskov (see e.g. https://news.ycombinator.com/item?id=36879311). Concerning the generally accepted meaning of OOP see e.g. https://ethw.org/Milestones:Object-Oriented_Programming,_196....
> We should encourage all software engineers to strive for knowledge, learn, and develop critical thinking rather than forget all kinds of rational behavior, considering only the hype and prejudice of our times
All too true, and increasingly forgotten.