I'm not very fond of the stance they take, and the fact that many rabbanim allow what they are machmir on makes people less trusting and less open to listening to them. If someone told me AKO says my drink is no good, I would likely have a similar response to the guy in the story. Not due to ignorance but because the psak I got was that it's kosher l'chatchilah.
Refreshers are a serious problem, you don't even have bittul b'shesh, it's mostly grape juice.