If you want to attack the article, you can pull out bits and pieces of it to do so, but it's written by diabetes specialists who are responding to misconceptions about juice that they see in their clinic every day. The vast majority of their clients are drinking commercial fruit juice, not carefully measured made at home smoothies.
I'd have appreciated reading this article years ago before I knew anything about nutrition and thought the smoothies I was drinking from Jamba Juice were good for me. They weren't and contributed to my being 40 lbs overweight at the time.
So if this article gets a few people to reconsider (or even think about) their conceptions about juice, then bravo.
Blended fruit retains everything that makes fruit good for you, including the fiber and pulp.
Juice doesn't, effectively making it sugar water with some nutrition.