I would say "creative" workers instead of "knowledge" workers. If your job is to regurgitate a bunch of stuff from memory, interruptions might not be a big deal. If your job is to create new things that don’t exist yet, then interruptions derail you as you need intense clarity and focus to do so. And it affects everyone who is in a creative class job equally when they are in a creative mode: Designers, architects, musicians, writers, engineers, chefs, mathematicians, scientists, etc.
I like to think of it like this: A musician can play for a busy stadium, or a chef can cook for a busy restaurant, if they are playing a song they rehearsed or preparing a dish they made many times. But to write that song or create that dish in the first place, like hell you could do that with all that noise and distraction.