I don't believe any cats should be allowed around chickens, same with dogs. Sooner or later they give in to their dark side.
I am sure some do partake of the "dark side" as do most animals - either for food or sport. We also see the dark side in humans everyday.
That said, I have had chickens most of my life along with almost all other farm animals and poultry. There has always been cats and dogs, including a pet armadillo, skunk, and groundhog.
The only domestic loss we suffered was via a dog - one of my own and another that belonged to someone else.
Mine didn't get to stay a farm dog.
I can't say what happened to the neighbor's dog. It came back twice, but never after that.
However, over the span of 60 years, I have never lost a chick or duckling to a cat - although I had a hawk take a duckling right in front of me. The birds here and especially the ducks and turkeys - have gone after neighbor cats when they have passed through. They don't come by often.
I have one Australorp hen who goes after both the ducks and turkeys, so I have no problem thinking she could handle a cat if she thought it was necessary.
It boils down to individual choices, I guess and - as you said - the personality of any domestic animal (or human).
