This is, an indictment on just how different cultures can be completely ignorant of one another's idiosyncrasies
When she said "I rebuke you in the name of Jesus" as a black person, I recognised that as a light hearted attempt at being sarcastic, playing around, banter etc. it's something that is said often in the context of satire to poke fun at how over the top (typically) black church pastors can be and using things like holy water to 'cleanse' whoever needs saving.
Again - to me - that was clear from the outset.
To someone who isn't familar or hasn't been to a black church service, i'm sure it's strange and confusing - and in this cops mind, he clearly took it as a threat.
Just a complete failure in policing and highlights the importance of having people in positions of power who can understand the people that they serve.