Exactly. Even for teachers who don't spend much of their time sitting at the desk, they still need desks. If this principal blames the desks for the bad teachers, perhaps it's not the desks that should be gotten rid of.
Performing a BING search, I found a lot of advise that interactive teaching is better than sitting behind a desk. I even found a survey of students who perceived mobile teachers as more effective than desk teachers. Although this advise instinctively makes sense, I could not find a study to confirm this. Opinion makes lousy science. I can recall some of my best teachers that sat at a desk or just lectured from a podium. Should my experience now be fact? Should I advocate for desks and podiums and remove smart boards?
What is hurting public education is year after year implementing the "new idea" or the "new method" without proven studies to show these gimmicks work. However, I believe most school administrations enjoy the constant change because it lowers accountability to measure their decision on curriculum and teaching methods.