I wonder if it's more about her being a female who is in power and not ever backing down. Some people can't stand it. Some try hard to knock her from her pedestal, but she keeps forging ahead. So then people start making crazy things up, like convincing people she's part of some satanist occult.
This isn't new though. She's been accused of this for decades, but you are right she is far too tame for those with common sense to buy into this narrative.