A multitude of reasons but mainly imo because those creators have not yet had a conversion experience with Jesus Christ.
The creators of this new religion would say it's you who hasn't had a conversion experience with their their particular deity.
Not really, no. (wouldn't really use the term magic but I think I know what you mean)
Off the top of my head, in Exodus, Aaron and Moses have a throwndown with the Pharaoh's magicians. Staffs turn into snakes, and crazy stuff happens. Sounds pretty magical to me.
Yes, and also dangerous if what I have read about it is true.
Now now, those are just your Thetans talking