The only reason I could see would be that it paints organic farming in a negative light, and thus a lurker might see it and think organic is "bad", but that is a pretty hard stretch I admit.
I do not feel that way, but just citing a potential reason???
But I have always wondered about plastic in organic farming myself. Not that regular agriculture is any better. On the
dairy farm we spent $3000 a year on plastic for silage covering alone...and that was reusing all that we could.