Actually, I had the trash collector's job a couple of years back, only instead of trash, it was my job to open up the computer CPUs and blow the dust and lint out with a vacuum. I had to go through huge complexes that housed offices and warehouses for WalMart's distribution system. I absolutely hated it because of scenarios just like this - but - if someone was that busy (and they sometimes were), I cleaned elsewhere and came back (or checked it off as done and left it for next time). I wouldn't have considered arguing with someone over it. I was intruding in their space and their workday. I felt bad enough having to interrupt them at all. Some days I'd show up at one of those places, shuffle papers in my truck having an anxiety attack, and go home, rather than have to go through those immense places pestering strangers all day.
But in this story, the trash guy does seem a little cognitively impaired beyond just AS, and irrationally rigid. As was pointed out, how hard is it to reach under the desk and hand the wastebasket over? You could do that without even speaking, much less moving.