Building websites is programming. Writing HTML and CSS is programming. I am a programmer, and if you're here, reading CSS-Tricks, chances are you're a programmer, too.
The thing is, the details in programming layout with CSS are different, for example, than the details in programming API endpoints with Ruby. Or machine learning with Python. Or programming a browser engine with C++.
But those differences are details! A lot of details, but still... details. It's all programming.
Source: We are Programmers, an article by Lara Schenck.