If the view outlined here is correct, namely that people cannot really grasp the nature of the suffering which their behaviour creates without wishing to refrain from it, you may ask how do experimenters, factory farmers, cattle transporters, etc., carry on? The answer is, in one way or another, I believe, that they do not really grasp what they are doing. At some level it may be right to say Forgive them, for they know not what they do. But the immediate task is to make people realise sufficiently what they, or others on their behalf, are doing, so that it will be done no more.
pp. 94-95 - The Animal Welfare Movement and the Foundations of Ethics