How can a pilot who has just landed on a runway with no turn offs (long grass) do anything other than backtrack? As the landing isn't over until the aircraft is clear of the active runway, SS in these circumstances is not technically in an aircraft manouvering, he is in an aircraft landing. Unless the chap behind him had an emergency then SS has priority until such time as he clears the active.
I know it's easy to say sitting in the comfort of home but I would have been tempted not to hurry to get out of this arseholes way and continued to taxi back to the end of the runway. Alternatively, if I'd felt my safety was threatened enough I'd consider coming to a stop, shutting down and getting out for a ciggie and see what Mr. Hotshot did with the situation.
Once I felt safe enough I'd clear the active for him to land. If his tone was as condesceding as I'm interpreting it, then I'd have chinned him.
