That is true what did they expect,if you leave any animal on their own they are going to survive the best way that they can and Cats being the supreme hunter are going to hunt.
I sadly have noticed this with Terrance , Gregory and Joey.
When I let Mr Purr Michael out years ago he and Scratchy and another Cat killed a neighbor's Easter Bunny!!!
That is sad that Cats will take the blame for poor Guardians.