It’s similar to any tech buzzword. Take “agile” for example. Agile was successfully sold as being a great idea without really being well-defined. Suddenly anyone selling a development methodology had a strong incentive to pitch it as being the real way to do agile development.

In the 90s and 2000s every 10x california tech guru agreed that OO was the future, but apparently none of them actually liked smalltalk. Instead, every new language with a hint of dynamic dispatch suddenly claimed to represent the truest virtues of OO.

There are also people who argue that smalltalk is not true OO. They say that by Alan Kay’s own definition the most OO language is Erlang.

I think it’s most useful to learn about that history, instead of worrying about people’s post-hoc academic definitions.