Why is it OK to criticize OOP using non-pure OO languages like Java, C#, or C++? Pure functional nut cases like Don Stewart and Simon Payton-Jones (whose favorite pet example of a dangerous side effect is a nuclear holocaust) don't have to defend FP from critics whose only experience with FP comes from non-pure functional languages like Python, JavaScript, and now Java and C++. Yet here we are again, with another under-informed, overly-prominent person publicly airing his grievances with Java as if all OO languages bear some collective guilt for them.

Smalltalk is not a hard language to learn. Haskell is far, far more complicated. You can download Squeak/Pharo/whatever and learn the language in a few hours. Why in 2012 is Java still such a potent argument against the entire paradigm of OOP, both class-based and prototype-based? Why does OOP alone have to put up with this sort of scurrilous, intellectually lazy and dishonest propaganda against it?

I agree fully - reading through these comments is frustrating, as the languages mentioned can hardly be called Object Oriented. Learning Smalltalk is something everyone who really wants to understand OOP should do. C++, Java and the like really should be called Class Oriented languages, as demonstrated by the often very deep class hierarchies. It's not about the classes, it's about the communication between objects. Objective-C is far closer to Smalltalk than most of the languages mentioned in these comments.

The downside to learning Smalltalk - the realization that a 30 year old environment is more advanced than whatever modern tools you will need to return to to earn a living.