I'm suprised how many programmers think polymorphism is exclusively an OOP thing.

Check out how many think OOP is the opposite of FP.

Probably a symptom of not knowing multiple languages/paradigms in-depth. Without that point of comparison you can't tell apart language features from OOP etc.

The mainstream languages lack a mighty ML-style type system. Users only knowing that languages do actually only see polymorphism manifested as traits/mixins and inheritance.

I'm terrified of how many people don't know what polymorphism is - and even less people who can utilize it.

(I'm serious. Most people can give a definition of what polymorphism means, but utilize it in the most hideous ways possible)

Inheritance is not also a part of OOP, Cpp and Java misleads people.