Re: mumbo jumbo
what you gonna do if you have an operation on several types that are hierarchically unrelated to each other
That's why C++ has multiple inheritance - and languages like java and C# have interfaces.
Most decent programmers were largely implementing the principles of object-oriented programming before it was a thing - the language features are just supposed to facilitate it. Unfortunately, it seems to have become radically theologised - though, as you imply, a number of its former adherents are now proselytes to FP: and there's no-one as devout as a convert...