Unfortunately the article is a jumbled mess, and if there was a concrete point in there it was certainly lost. That aside, yes the realtor industry is threatened by all the major RE sites. For good reason, one way or another it will disrupt the status quo. How far and how quickly remains to be seen. As for errors on the site, that's a human and/or technology issue/limitation where they exist. May be Zillow's issue, may be issues downstream.
Those who fight the Zillow's of the world will be harmed in the fight, just as the record industry and countless other industries have been in the past. Most "regular home buyers" (non realtor and/or investor) I know use these sites as starting places to find homes to buy. They then call their realtor with a list of homes they want to see or go direct to an open house. If your homes aren't on there, you certainly may miss out on potential buyers.
Fighting them may feel good, but they are here to stay. Like the record industry did (well, sort of...), eventually realtors will have to figure out how to work profitably in the new technology age or go the way of the buggy whip. (I know many realtors are forward thinking on this, lest anyone think I'm lumping all realtors in with this poster.)