In fact if one person is unkind to an animal it is considered to be cruelty, but where a lot of people are unkind to a lot of animals, especially in the name of commerce, the cruelty is condoned and, once large sums of money are at stake, will be defended to the last by otherwise intelligent people.

Animal Machines (1964; rev. ed. Boston: CABI, 2013), ch. IX, p. 175.