Why is this ok for cat owners and cat fans?

Look at this. It's absolutely horrible. Why do people let their cat roam free outside when they torture small animals to death? They don't even have to kill because they are hungry. Cats have this natural hunting instinct that's essentially like playing an entertaining game to them(Source: Google).

Not for the faint of heart. The cat killed the poor black bird:

https://www.youtube.com/watch?v=fz2D4qGFXjw

Like seriously. House cats just as the name suggests belong inside the house. Not outside. They are not called outside cats for a reason. When this is a problem for you why let your cat roam free?