Why does many people abuse humans, dogs, cats and other animals?

Why are many persons cruel to human and other non-human animals?
I often try to think that what made a person become so destroyed that he/she feels it is justified to inflict so much violence against another sentient being; and lacks the capacity to feel empathy and love when it comes to the suffering of another individual.

I also think that if this person would have been taught love and compassion from childhood, instead of violence and apathy towards other individuals suffering that this person would have been completely different.

If we hurt another being, we hurt ourselves. In order to kill someone, we have to violate this individual's love and wants, we have to crush hopes, destroy a family and friend relationships; We have to sacrifice part of our inner love and compassion; we have to say to ourselves that 'I don't care' in order to take someone's purpose and life. And this has destroyed us, destroyed our society. The reason why people inflict violence and suffering upon others is the lack of empathy and love to others. If we instead would reinforce love and empathy at each meal by living a vegan lifestyle, instead of destroying parts of our love and empathy at each meal by hurting and killing someone for 'convenience' or taste, we would surely attain world peace. As long as we sow violence and wars by our eating choices, our society and culture will be absorbed in violence and wars.

So the problem is that our society destroys a person so much. The society inflicts violence upon a person, it teaches a person to practise violence, and the person loses more of his/her innate love and compassion. We will never reverse this destructive force and a persons lack of empathy, by feeling and practising violence and hate --- in our actions, speech and thoughts. If we feel violence in our heart, it will also effect our actions, and it will make us less efficient in our vegan advoacy. To show compassion, love and nonviolence in active vegan education of those we meet is the only thing that can make a people experience a revolution of their heart and go vegan.
That another one has abused an animal, doesn't justify a violent revenge action.

So when a person is hating and destryoing for other individuals, I don't feel hate. I feel a deep sorrow for the individual that has been hurt, and I also feel sorry for the individual that has been destroyed by the choices that our society to a large extent has enforced upon that individual. Of course we are all responsible for our choices.... But I know that the person would have been totally different if we had lived in a completely vegan society with no discrimination at all - not against humans and not against nonhuman animals.

We have all been destroyed to a large extent, and more than 99% of the population still is regularly making non-vegan choices, hurting and killing animals on a regular basis. Our non-vegan friends are condemning dog abusers, but are abusing animals themselves: http://www.abolitionistapproach.com/a-note-about-michael-vick/
I also recommend this wonderful essay on nonviolence: http://www.abolitionistapproach.com/a-comment-on-violence/