I doubt very much they would agree with their characterization as sadists, but I also doubt they would be willing to pay for perpetual-upkeep progesterone, (or whatever the animal equivalent might be) for their animal children. It's a wonderful intersection of convenient and cheap, and because animals are defined as being unable to consent (without the restrictions that would normally impose on a human subject), you don't have to worry about pesky things like morality or ethical restrictions. By grabthar's hammer, what a savings.