If the Doctor isn't around, security measures lock it down, even preventing the use of keys.
After a long build up explaining just how serious the fairy circle is, it turns out no that’s just racist
I took that as a reference to how people don't believe in it, but that doesn't stop it from being real.
Dr Who magic isn't Tinkerbell magic, people don't need to believe in it for it to work.
So this woman makes everyone near her hate Ruby. Everyone. Why? Who fucking knows
I think it's not that she "says" anything, it's that standing next to an old her, and looking at present her "breaks their brains" due to fairy magic and perception filter being crammed together. They likely still just see the blur, but subconsciously the paradox ducks with them. Like how when multi doctor episodes happen, the younger versions forget it.
Then she goes back in time. How? Why? No idea. It just happens and you gotta deal with it.
Everything weird is because of the intersection of magic and time travel fields... Someone getting thrown back into time isn't that off the wall. Especially if viewing her life and the fairy circle as two never ending loops.
This. Makes. No. Sense.
It's Dr Who mate... Unbelievable things happen every episode, but will likely eventually be explained by really advanced tech
So as far as this season supposed to be supernatural...
That's not new, in Dr Who the British royal family are all werewolves and vampires are real just aliens.
Any sufficiently advanced tech is indistinguishable from magic. Even the Doctors tech is often confused with magic. It's entirely possible all the "magic" is going to be tech from some alien species (maybe more than one) living among humans for a very long time even under the Doctor's radar.
This year I think they're just waiting instead of explaining it away with timely whiney bits until later in the season when it all gets tied up with a bow.