I think he’s sounds a little ott. However I can see where he’s coming from in some ways as a lanyards left out, books out, etc aren’t a problem in themselves but combined leave it cluttered.
But why is it the end of the world for a room to be a bit cluttered for a bit? It's not like the OP has left things out for days at a time or spread her work out across the entire house.
Homes are to be lived in - not every surface has to be clear 24/7 - and if you can't put your work lanyard down on the nearest surface while you run to the loo for a post-work wee or take a break from your work for an hour without have to completely put away what you are working on at home, then where can you?
I am doing some online courses for work once a week, we start at 9am, have lunch 12-2 and then back to the zoom meeting till 5pm. My desk is in the living room and I usually have it 100% cleared off but during my course I have my ring light (lighting in my flat sucks so I need it to not be in darkness), tablet and tablet stand, course pack, reference books, notebook, phone, pens/highlighters, sticky notes and my insulated coffee mug on the desk.
When we break for lunch I could put everything away but why would I waste time tidying up stuff I will have to get out (and put back in the exact same place) in an hour or so? If I needed to clear the space (eg if I was working from the dining table and needed needed space to be able to eat lunch) then it would make sense to tidy it all up, but since I don't need my desk space between 12-2pm I leave it in situ. At 5pm (unless I have stuff to sit and review after the class), everything gets tidied away and returned to its permanent home because that's when I am finished with it.
I have also had friends round during my lunch break without feeling the need to clear my desk - everyone knows it is my course day and therefore it is "normal clutter" for my desk to look like its in use... if it was piled high with papers on Friday then it would be "unreasonable clutter" by that point.