You're... not addressing my points. You're giving me examples of things I find immoral from the Bible in an attempt to justify the things that I find immoral in the Bible. Please try again without appealing to Scripture this time. Appeal to reason.
Why, on the "Christian Theology" forum, should we appeal to reason instead of God?
What's more, you included God when you framed your question to us in the first place:
("That's what I am asking: how do you reconcile the claim that God is omnibenevolent with the commandments given by God to people to cause pain and death").
However, if there is an answer to your question that does not take account of God's will and his revelation, it would be that animals, when killed, provide food that is necessary for good health, plus also such additional benefits as medical research, clothing, and various tools or equipment that make our lives easier. That's from reason.
In addition, your imagining is shortsighted. A world with eight billion human inhabitants plus many animal species could not support all of these totally on vegetables. Yes, for the small number of people who are vegans, it's fine for them, but it would not work if that were required of everyone.
Also, what you are imagining is a world that would not have anything else that we derive from animals but that isn't food. Your concern that cruelty to animals not be part of the human experience omits the fact that we cause pain to animals when men in less advanced parts of the world continue to ride horses or camels or hitch animals to plows, etc.. That's without them eating the animals.
Try imagining a
world in which billions of people have to press every last acre into the production of grains and vegetables, deforesting the woodlots that produce oxygen for the atmosphere and destroying the viability of many animal species in the process.