I think its because they are smaller and there for they have less impact.
Diana your picture was a great shot but if you had cropped it in on the fish a bit more it would off made more impact in a reduced size.
I am sure Jason had too make them smaller so they would fit. This means they were run through the photo butcher.... we did have a lot of entry's this month.
I always base my vote off the originals though and I would think think that the majority of us do as well.
Ps I always shoot macro on a macro lens and almost never crop makes for a cleaner photo.
That being said where is nexts month subject???