Peculiar article. He says the health benefits are unsubstantiated (mostly true) but then after dismissing almost all of what is said about kombucha he goes on to give some completely unsubstantiated reports of the very rare negative claims. If we're just going on completely unsubstantiated information from the public, it's obviously overwhelmingly positive. He stoops to using a negative like lead poisoning from brewing in ceramic containers! Even neglecting to mention that this would be fine unless you were using a lead glaze, and who the heck is going to brew kombucha in a lead-glazed pot?
I hate to sound like one of those 'modern medicine is a load of big brother big money conspiracy' type crackpots, but his motive seems purely to dissuade people from alternative health products. I do agree though that if you have a serious medical problem you should be seeking proper help and not relying on something like kombucha. It's a healthy thing to consume, not a medicine. It's a shame this guy gives credibility to the 'doctors are evil' camp.