Simula is basically C++ before C++, and we know C++ is not OOP in the original sense. When OOP was first defined, it was quite explicitly noted that C++ is not OOP. Java's object model follows in the same vein as this lineage. These are not OOP languages, as originally conceived.
Furthermore, message passing was the defining feature of OOP. Of course it was. That is the distinction OOP was calling attention to – what made OOP different from the other object-based languages that had been around for decades beforehand. Nobody was going to randomly come up with OOP out of the blue to describe a programming model from the long ago past. Method calling may be superficially similar, but OOP was coined to call attention to what difference there is.
You are, of course, quite free to come up with your own redefinition of OOP that includes Simula, C++, Java, whatever you wish. You would not be the first. However, as we are talking about the original definition, whatever you want to define it as does not apply. It is not your definition that is under discussion.
