I agree with you that when animals are slaughtered, it should be quick and painless.
The video below, unlike what you posted, does show the actual killing of a hog. The animal is shot in the head and then its throat is slit.
Although, naturally, there is a lot of blood, there is no fear on the part of the animal, or even awareness for that matter of what is happening. Interestingly, the other pigs in the enclosure don't seem to panic at all or even notice what took place.
Humane killing of hog - YouTube
I think that butchers, whether they are Muslims or Jews or Christians or atheists or people of other beliefs... anyone who kills an animal for food... should do it in the quickest and least painful way possible.