A cat that from a very young age* has been raised by humans does have a different psychology than one that was raised by another cat. I have observed several cats who were raised this way and they tend to be more human focused than other cats. They may not interact completely normally with other cats, but can learn normal cat-like behavior over time if given enough exposure to other cats.
As far as violence between cats go, this is normal cat behavior. Normal cats can and do defend what they see as their territory from strange cats that trespass. A cats territory includes people and food in that territory as well.
(*Normally the 'very young age' is approximately around the time the kitten opens its eyes or younger. If a cat has any exposure to another cat (usually its mother) after this, it tends to have normal cat behavior.)