By using the term cruelty-free, are you describing dense, commercial feedlot animal production only, or are you including all types of animal husbandry and meat acquisition, including hunting?
There's a definite spectrum of cruelty, with factory farming near one extreme and many forms of hunting near the other. How much cruelty one can stomach (literally, in this case) is up to the individual, of course.
And yet animals (even herbivores) kill other animals all the time. This concern over the cruelty of killing livestock for food is such a weird human conceit.