Yeah but that's what I mean by using it as a tool, you're not trying to model some weird taxonomy with your classes (like the square/rectangle situation), you're using a language feature to enable generic code and/or for code reuse, any real-world relationship between the concepts is irrelevant.

Inheritance is bad because it enforces a subtyping relationship alongside code reuse and data reuse. It is extremely rare you want all 3 together and even when you think you do there's a rude awakening coming your way, specially if you did the "model real world concepts as a class hierarchy thing."

The object-relational mismatch is a weakness of the object side, not of the relational. Use the right tool for the job and forget about stupid programming paradigms.