The subject came up when the person was critical of Star Trek because (according to him) it had been written by L. Ron Hubbard. When my friend told him that wasn't true the anonymite insisted it was.
Next he told my friend that Scientologists worship Dianetics or something to do with Dianetics (it was hard to understand what he was meaning). When my friend told him this was not correct he still insisted it was.
He said a bunch of other incorrect things, one of which is a misconception I've come across a lot in comments that have been made on my blog - he completely misunderstood the term "thetan". (I cover what it really means here: The Secrets of Scientology, the anonymite had the same weird "alien ghosts" idea that I cover in the linked post.)
The bottom line is that this anonymous guy has fallen into the same trap that people have been falling into for millennia: Someone doesn't like some other person or group so he tells lies about them and tries to make them seem weird so that others will help him to attack them.
Unfortunately there are many people out there who are easily led. When they encounter a group being demonized they just join in. If I were to be kind I would excuse them by saying that maybe they don't have any concept of history and how often this "demonizing" method has been used in the past or maybe they are not very bright and can't easily tell truth from lies. If I were to be less charitable then I would say it is just an excuse to unleash their hatred and if it wasn't Scientology then they'd find something else to attack.
But whatever the reason behind it, I would request of these people that they at least find out what they are attacking before they attack it.