Excuse me for thinking negatively on why someone would do this, but here's my theory. I think that the 1's come from people that feel they have half a chance at getting a ribbon. Maybe no one felt threatened by your EXIT photo (no offense) so therefore the one's weren't necessary. I remember your Kiwi photo, it was obvious from the very first glance for me that it would certainly score well. Maybe others thought that too and wanted to take you down a bit so they'd hopefully remain in the race for a ribbon.
I could be way off and it's just a thought from reading and thinking your post.
No ones on any of my six highest rated entries. Maybe it's not so hard to avoid the 1s as the popular perception holds. Good photos that fit the challenge and are not trying to bust down the box seem to do it for me. But, then again, I don't have any blue ribbons.