Yeah, I don't buy that either.
I know that the best software engineering work I've done in my entire life happened when I was working as a hotel housekeeper, before I was programming professionally.
It was because cleaning hotel rooms is a purely physical, and highly repetitive job. Every day at work, I was mentally "checked out", working on difficult programming problems in my head while my body just robotically did the work.
Once I was programming professionally, I no longer had the luxury of spending so much time deeply thinking about programming problems.