Your parent implies that not getting functional programming concepts makes one a "blue collar" (i.e., less sophisticated, more commodity) programmer. Presumably, understanding functional programming is one necessary requirement of upgrading to "white collar" (i.e., more sophisticated, less replaceable) programmer.

I'm guessing he's implying that "white collar" programmers have a degree in Computer Science that is heavy in theory (as opposed to being primarily vocational, like, say, the University of Phoenix). Most such curricula will include at least one class that focuses on functional programming. (UC Berkeley teaches their 101 CS class using Scheme!)

The people who care about this distinction are the sort of people who give job interviews where they ask you to implement a balanced binary search tree on the whiteboard and then grill you on the order of growth of each function that you wrote. :-)

"Blue collar" is a common expression to describe developers without CS background, that usually develop CRUD applications and are expected to be easily replaced by management.

"What do I need to do to upgrade to white collar?"

Develop a stubborn willingness to ignore the at-times unsatisfactory performance of immutable data structures.