It's just the latest hipster language trend. When OO was new, structural C was evil. When functional programming happened, everything before that was evil...

Because, yes, sharing state among classes for code reuse, is fundamentally evil... How dare you want to couple state and logic?

Almost like every single UI framework in every mainstream language has converged upon OO as the best way to model the problem at hand... GTk even invented a similar type system to what was mentioned in this PDF just to give C OOP constructs... Now witness as the Rust language has failed to produce a compelling UI/widgeting framework or paradigm, and the best ones out there are Qt-based or GTk-bindings (letting C hilariously handle the OOP for Rust).