The difference is my dog stays in my garden so there's no harm in her being out there, still on my property. If you can keep your cat in your yard I have no problem with you letting them outside but to have a cat that you deliberately release outdoors every day with no plan for containing them, and then abdicate responsibility for what happens to it because 'you can't control where they go' is a massive cop out. You can control it (by keeping them inside or building a cat run) you just choose not to. Your cats life, the local biodiversity, neighbours pets and gardens etc are all less important than your own laziness and refusal to take responsibility for your pet.