Well, of course OOP isn't required for a good design. What I'm saying is that, as far as not redefining functionality for different types, it doesn't work against it. At least not if we allow for static polymorphism, and I'm pretty sure that's considered an integral part of object orientation; at least I remember Kay talking about it.
Static polymorphism wasn’t part of OO originally; in Smalltalk, everything was late-bound. And you can of course write things generically even in the “classes and methods” kind of OO, but I think the culture around that paradigm encourages coding non-generically. You might say OO itself works toward genericity, but some OO-branded languages work against it.
