Very little of the great cruelty shown by men can really be attributed to cruel instinct. Most of it comes from thoughtlessness or inherited habit.The roots of cruelty, therefore, are not so much strong as widespread.But the time must come when inhumanity protected by custom and thoughtlessness will succumb before humanity championed by thought.
Cruelty is easy, and it breeds only misery. Kindness is harder, and you have to be brave to give it. To be cruel, you can stay closed off from everyone, wear a mask, but to be kind, in essence, to show love, you have to make yourself vulnerable, show your true self to someone and open yourself up to rejection.
If one person is unkind to an animal, it is considered to be cruelty, but where a lot of people are unkind to animals, especially in the name of commerce, the cruelty is condoned and, once sums of money are at stake, will be defended to the last by otherwise intelligent people.
Such is the common process of marriage. A youth and maiden meeting by chance, or brought together by artifice, exchange glances, reciprocate civilities, go home, and dream of one another. Having little to divert attention, or diversify thought, they find themselves uneasy when they are apart, and therefore conclude that they shall be happy together. They marry, and discover what nothing but voluntary blindness had before concealed; they wear out life in altercations, and charge nature with cruelty.