Brian McKenna is a public figure who people could easily have encountered in other ways.<p>In my experience many functional programmers, myself included, <i>do</i> generalize where they don&#x27;t need to (e.g. writing a function to accept any F[_]: Foldable when it&#x27;s only ever called with List). At which point asking them to justify the abstraction is entirely justified. Conversely in cases where fancy functional techniques really are improving maintainability it&#x27;s usually pretty easy to demonstrate this by comparing two implementations side by side.