Agreed... I am both a bird lover and a cat lover and have frequently kept both. My only thought was metaphorical. It's a daft expression I agree when you think about it.. it would indeed be cruel in the highest degree to literally put a cat among pigeons. I have a cat/pigeon related story to tell at the end.. but metaphorically is it always cruel and manipulative? I think not always :)
SO the cat and pigeon story... I have a cat-proof garden,, they can't get out, birds can get in.. I have also, in this garden, a feline home from home, a feline des-res and several felines were in residence one day.. somehow a pigeon got in there.. did the felines catch it? I cannot imagine so as the bird was completely unharmed when I went, saw it there and let it out.. The cats were literally asleep in their beds and taking no notice of the bird... So I can only think that these cats are excessively stupid.. they truly wouldn't know what to do with a pigeon if they caught one..