for example, halal slaughter. After reading about how an animal is killed according to halal means, I realized "wow...that causes the animal to suffer a lot." It is a matter of "This makes no sense......but ok"
We can observe that in their natural rôle, sheep are meant to be natural prey for predators like wolves.
The wolves follow a herd of sheep, single out the individual animal that they have earmarked for consumption, attack this animal by insistently persecuting it by running after it, and then apprehend their prey, resolutely target its throat, firmly bite its throat, and then ensure that the prey keeps bleeding from its throat until it dies. Next, they proceed by devouring it.
Why does this matter?
Well, it is obviously the benchmark for what is permissible. Some people may think that nature is cruel. However, it is not our job to admonish the laws of nature on their morality. That is obviously the exclusive prerogative of the creator of nature himself, the One True God.
In the end, we are talking about animals that were specifically designed to be eaten by the their predators. That is their role in life. They are simply supposed to be caught at the end of their lives and be rather unceremoniously eaten. The fundamental nature of a prey animal is that it is simply meant to be someone's future lunch running loose, until they finally fulfill their pre-programmed job, and end up in another creature's stomach. It does not matter at all if you like this idea or not, because that is the way it is meant to be. Who are we to overrule the laws of nature?
Does the animal suffer from its inevitable fate? Possibly, but I don't think so, actually. The mechanisms of life are in fact quite palatable. It is as claiming that women suffer a lot when they give birth. To some extent it is true, but apparently, they quickly forget that kind of tortures when they see the newborn child. Therefore, there is no need to try to spare anyone from the details of their natural rôles in nature.
Therefore, human slaughtering methods must just ascertain that they are not more cruel than what the animal would suffer in nature.
In my impression, halal slaughtering methods certainly satisfy this requirement.
Anybody who objects to this, should basically create his own planet, design his own animals, and then institute rules that he believes are less cruel. It is quite likely that his new planet is not going to work that well. He will inevitably introduce inconsistencies, by lack of competence and because of wishful thinking, and end up creating a much more cruel world than the one he thought was already cruel and that he was going to improve. Therefore, just face the truth. Since you are not capable of creating such new planet with other and better rules, what makes you believe that you are capable of "improving" the rules of the existing planet?
It is a bit like how the Soviet Union was going to solve the problem of income inequality, but in reality ended up creating the most unequal system ever seen in the history of mankind.
You see, quite a few people are simply not capable of understanding their own limitations. They are several orders of magnitude less intelligent than they think they are. Seriously. That is not such a big problem. It only becomes one, when they also want to impose their stupidity onto others. Then, they are not just idiots. They are evil idiots.
Ultimately, all of this can only lead to these evil idiots having to prove that they are willing to risk their lives and die for what they believe in - which they almost never want to do -- instead of whining when someone else who believes the opposite of what they believe, proves that he actually is.
