How do people ‘act’ against demons?
Another inquisition of those they consider in league with them?
However large, the number of people who will believe the aliens to be demons will be small compared to those that don’t. They will be considered a kooky minority to be marginalized. They will not be in a position to launch any sort of inquisition. It will be they who will be more likely to become victims of a secular inquisition.
Let me hasten to add that these are anecdotal reports (of course).