As other sibling comments have said, it's cultural. Fortunately, there's some push toward functional & ADT-style modelling in the Java community and they've decided to call it "data-oriented programming" for some reason.

Eh, I don't think Java type system is strict, nor is it the root cause of this cargo cult mess. It's probably due to many enterprise programmers who think design patterns are the building blocks of everything rather than an invisible, emergent structure.