They love, because they were born in a litter of kitties. They received love from their mother kitty and their siblings. They become independent, and stay fiercly independent but still they like to have kitty cat friends or human friends. It's not weird..
Some live together, or create a family. I think of it more like a fraternity or sorority house though. Because they are still individuals (they hunt individually) but come together at night or during the day.
Some cats at my old barn befriended my horse. My horse makes friends with all sorts of animals though. His best buddy was a hen, lol.