…but you may bring in any number of animals to be slaughtered: It’ll be all right for the vast majority of people. One million, one hundred million or a billion animals. It’s all right. As long as the corpses of all those animals will be eaten up by humans it’s no problem.
Now reveal yourself as an antinatalist suggesting it would be ethical to sterilise a billion sentient animals in order to reduce suffering. People will be flabbergasted calling you immoral.
In a similar manner people are prepared to sacrifice own children to life’s imponderabilities and to lingering illness at the end of their lifes, while they are not prepared to consider abstention from procreation.