It is very silly, but conservatives (and others, probably) would call them hypocrites if they didn't discuss the humane treatment of ALL animals/insects. On principle they have to.
Just like the Catholic church: it calls itself "pro-life", so it is against abortion, war, and the death penalty, which isn't true of most "pro-life" people in the US, for example. As stupid as it sounds to us, they are, after all, "People for the Ethical Treatment of Animals"!