Really? Which "pagan circles"? Where? Prove it.
I've only read the "isis/horus/seb" garbage in one place.
The early Jehovah’s Witnesses made a similar silly claim, only when I first read it, the ‘S’ was said to stand for “Set.”
I’ve pretty much decided that such nonsense and things like attacks on Nicene or Chalcedonian ideas are like smoke or chaff. Life is too short.