Plant RNA Paper Questioned!!

The paper by Zhang et al (which has been discussed in one of our seminars) describes how plant miRNA molecules that enter animal systems after ingestion inhibit proteins that aid removal of LDL in the bloodstream. This paper however, had been through rough weather as many a reviewer considered it to be "too extraordinary"?! which makes me think, how is it possible that any reviewer can disagree with an idea per se, when it is substantiated with results? Isn't it natural that they ask for further substantiation of the results rather than reject it by simply saying 'too extraordinary!'? I wonder if there is a rulebook to abide by. If not, it is high time they had one.

http://the-scientist.com/2012/04/16/plant-rna-paper-questioned/