I'm quite torn about the utilitarian argument, that claims that it is justified to kill animals for their meat as long as we give them better lives than they wo

I'm quite torn about the utilitarian argument, that claims that it is justified to kill animals for their meat as long as we give them better lives than they would have in nature. I have used this argument myself, but it occurred to me that you could use a similar argument to defend human slavery: why should it not be legal to buy a slave from a poor country where there's famine and war? You could provide your slave with an objectively better, safer, and more comfortable life, and it's unlikely someone else would help them. I don't buy that argument at all though, so I'm not sure I should buy the quality-of-life argument for farm animals. But I'm not really sure and I've gone back and forth on this, would love to see some other thoughts on this.