There is often room for improvements, including reducing pre-slaughter stress, but when done right kosher slaughter is among the most humane forms of killing an animal. For example, with a skilled _shochet_ a cow can collapse within 10 seconds and not react at all to the cut itself. The requirements for even the sharpness of the knife are paramount, such that the animal feel no/a minimum of pain. Contrast this with the overwhelming majority of slaughterhouses, both today and over human history, and I hope you’ll see that kosher animal killing is far different from what you described above.